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7th Grade > Mathematics

ALGEBRAIC EXPRESSIONS MCQs

Total Questions : 116 | Page 1 of 12 pages
Question 1. Find the value of the polynomial a3+3a2b+2abb2 at a=2 and b=3.  [2 MARKS]
 Discuss Question

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Steps: 1 Mark
Answer: 1 Mark
The value of the polynomial a3+3a2b+2abb2at a = -2 and b = 3
a3+3a2b+2abb2
On substituting the values of a and b in the above expression we get:
=(2)3+3×(2)2×3+2×(2)×332
=8+36129=7
So, thevalue of the polynomial a3+3a2b+2abb2 at a=2 and b=3 is 7.
Question 2. 1x; x0
is an algebraic expression. 
  1.    True
  2.    False
  3.    y + xy
  4.    2 (xy)
 Discuss Question
Answer: Option A. -> True
:
A
A single term or a combination of two or more terms joined by operators such as plus (+) or minus (-) signs forms an algebraic expression. E.g., 58 - y , 6xy + z etc.
So,1xisanalgebraicexpression.
Question 3. Define monomials, binomials, and trinomials. Classify the following into monomials, binomials and trinomials:  [4 MARKS]
(i) 4y7x
(ii) y2
(iii) x+yxy
(iv) 100
(v) abab
(vi) (53t)
(vii) 4p2q4pq2
(viii) 7mn
(ix) z23z+8
(x) a2+b2
(xi) z2+z
(xii) 1+x+x2
 Discuss Question

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Definition: 1 Mark
Classification: 3 Marks
Monomials: An expression with only one term is called monomial.
Binomial: An expression with two, unlike terms, is called a binomial.
Trinomial: An expression with three, unlike terms, is called a trinomial.
S.NOExpressionTypeofPolynomial(i)4y7zBinomial(ii)y2Monomial(iii)x+yxyTrinomial(iv)100Monomial(v)ababTrinomial(vi)53tBinomial(vii)4p2q4pq2Binomial(viii)7mnMonomial(ix)z23z+8Trinomial(x)a2+b2Binomial(xi)z2+zBinomial(xii)1+x+x2Trinomial
Question 4. Write the coefficients and terms of the algebraic expression 10x25x6. Also, find the value of the expression at x=2. [2 MARKS]
 Discuss Question

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Coefficients and terms: 0.5 Mark each
Value of the expression: 1 Mark
Coefficients of x2and x are 10 and - 5 respectively
Terms are 10x2, 5x and 6
We have to find the value of the expression at x=2 is
10×2×25×26
= 40106
= 24
Hence, the value of the expression at x=2is24
Question 5. Add  2a+3b+c+d, a+bcd and 3a4b2c2d. Find the value of the final expression if a=2, b=3, c=4, d=5. [3 MARKS]
 Discuss Question

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Forming the equation: 1 Mark
Sum: 1 Mark
Value: 1 Mark
We have to find the sum of the expressions
2a+3b+c+d,a+bcd
and 3a4b2c2d.

(2a+3b+c+d)+(a+bcd)+(3a4b2c2d)
2a+3b+c+da+bcd+3a4b2c2d
2aa+3a+3b+b4b+cc2c+dd2d
4a+0×b2c2d
Sum =4a2c2d
As per question ,
a = 2, b = 3, c = 4, d = 5
So, on substituting the values we get,
Sum = 4×22×42×5
=8810
= 10
The value of the expression is 10.
Question 6. Aliyah had Rs. 24 to spend on seven pencils. After buying them she had Rs. 10 left. How much did each pencil cost?  [4 MARKS]
 Discuss Question

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Forming the equation: 1 Mark
Steps: 2 Marks
Result: 1 Mark

Given that:
Total amount Aliyah had =Rs.24
Total number of pencils Aliyah bought =7
Total amount left after buying pencil =Rs.10
Total amount she spent
=Rs.24Rs.10=Rs.14

Total money spenton pencil = Rs 14
Let the cost each pencil be x
7x=Rs.14
Cost of each pencil ,x=147=Rs.2
The cost of each pencil is Rs2.
Question 7. Write the steps which should be followed to check if two terms are like or unlike.  Are x2y and xy like terms? [3 MARKS]
 Discuss Question

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Steps: 2 Marks
Answer: 1 Mark
Steps to be followed to decide whether the given terms are like or not are as followed:
i) Ignore the numerical coefficients.
ii) Check the variables in the terms. They must be same otherwise they are unlike terms.
iii) Next, check the powers of each variable in the terms. They should be the same and if they are not then they are not like terms.
We have to check if x2andxy are like terms.
The variables in both these expressions are xandy.
The power of y is equal in both the expressions.
But the power of x in the term x2y is 2, while in the term xy it is one.
The terms are not like.
Question 8. Remit's mother gave him Rs. 3xy2 and his father gave him Rs 5(xy2+2).Out of this total money, he spent Rs.(103xy2) on his birthday party. How much money is left with him? If x=2 and y=3 find the total amount left with him. [4 MARKS]
 Discuss Question

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Forming the equation: 1 Mark
Steps: 2 Marks
Result: 1 Mark
As per the question,
The amount of money given by Remits' motherRs3xy2.
The amount of money given by Remits'fatherRs5(xy2+2).
Total amount =3xy2+5xy2+10=3xy2+5xy2+10=8xy2+10
Total amount Remit spent =103xy2
Amount of money left =(8xy2+10)(103xy2)=8xy2+1010+3xy2=Rs.11xy2
Now if x=2andy=3, then on substituting the values we get,
Amount of money left with
= 11×2××3×3 = Rs198
Hence, the amount of money left with Remit isRs198.
Question 9. The number 5 is added to three times the product of two numbers, m, and n. What is the expression formed? What is the value of the expression if m is 4 and n is 5?  [2 MARKS]
 Discuss Question

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Forming the expression: 1 Mark
Value of expression: 1 Mark
The product of two numbers, m, and n is
m×n.
Three times the product is 3mn.

Adding 5to three times the product
=5 + 3mn

The expression formed is5 + 3mn
The value of the product at m = 4 and n = 5
=5+3×4×5=65
Hence, thevalue of the expression if m = 4 and n = 5 is 65.
Question 10. If 5 is added to three times the product of two numbers m and n, then the expression will be _______.
  1.    5+mn
  2.    5+3mn
  3.    m+3n+5
  4.    (mn+5)×3
 Discuss Question
Answer: Option B. -> 5+3mn
:
B
Analgebraic expressionis a mathematical phrase that can contain ordinary numbers, variables (likexory)and operators. According to the given question,
Three times the product of two numbers m and n is 3mn.
5 is added to three times the product of two numbers m and n.
The equation that represents this statement is 5+3mn.

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