Important Questions for Class 7 Chapter 12-Algebraic Expressions

Preparing for class 7 final exams and stuck with a tricky question? Don’t panic! For your benefit, our math subject experts have meticulously prepared a list of important questions for CBSE class 7 Math chapter-wise and topic-wise.

Important questions based on NCERT syllabus for Class 7 Chapter 12 - Algebraic Expressions:

Question 1: Simplify (a + b) (2a – 3b + c) – (2a – 3b) c.
Solution:
(a + b) (2a – 3b + c) – (2a – 3b)c
= [(a + b) (2a – 3b + c)] – [(2a – 3b) c]
= [2a^2 - 3ba + ac + 2ab-3b^2 +bc] - [2ac-3bc]
= 2a^2 -3ba +ac + 2ab - 3b^2 + bc - 2ac + 3bc
= 2a^2 -3b^2 –ab-ac + 4bc

Question 2: Aliyah had $24 to spend on seven pencils. After buying them she had $10 left. How much did each pencil cost?
Solution:
Let cost of each pencil be x
Total amount Aliyah had = $24
Total number of pencils Aliyah bought = 7
Total amount she spend = $24-$10 = $14
∴The algebraic expression of the given problem, 7x = 14
Cost of each pencil , x = 14/7 = $2

Question 3: The perimeter of a triangle is 6p^2 - 4p + 9 and two of its adjacent side are p^2 - 2p + 1 and 3p^2 - 5p + 3. Find third side of triangle
Solution:
Perimeter of the triangle = sum of the sides of the triangle
6p^2 - 4p + 9 = (p^2 - 2p + 1)+ (3p^2 - 5p + 3) + 3rd side
3rd side = 6p^2 - 4p + 9 –[(p^2 - 2p + 1)+ (3p^2 - 5p + 3)]
=6p^2 - 4p + 9 – (4p^2 -7p+4)
= 2p^2+3p+5