Grade 8 Revision Semester 1

Expand and simplify 4(7x + 3).

• 28x + 12

• 28x + 3

• 47x + 12

• 47x + 3

Simplify 3x + 2y - 2x + 3y.

• x + 5y

• 5x + 5y

• 5x + y

• 5x - 5y

Expand and simplify 3(x + 2) + 4(2x +1).

• 11x + 10

• 11x + 7

• 7x + 10

• 11x + 3

Determine the area for the diagrams below using algebraic expressions

• 10x² - 11x - 6

• 7x² - 11x - 6

• 10x² - 19x - 6

• 10x² + 11x - 6

Determine the area for the diagrams below using algebraic expressions

• 10x² - 11x - 6

• 7x² - 11x - 6

• 10x² - 19x - 6

• 10x² + 11x - 6

Determine the area for the diagrams below using algebraic expressions

• 10x² - 11x - 6

• 7x² - 11x - 6

• 10x² - 19x - 6

• 10x² + 11x - 6

Factorise ab+bc+pq+pr.

• a(b+c) + p(q+r)

• b(a+c) + p(q+r)

• b(a+b) + p(q+r)

• b(a+c) + q(p+r)

Factorise 2x + xy - 6 - 3y

• x (2 + y) - 3(2 + y)
• (2 + y)(x - 3)
• x (2 + y) - 3(2 - y)
• (2 + y)(x + 3)

Factorised form of 144k² - 81 is __________.

• (12k + 9)(12k + 9)

• (12k - 9)(12k - 9)

• (12k + 9)(12k - 9)

• (12k + 9)

Answer explanation

Option 3 is correct as by identity (a + b)(a – b) = a²–b², we can write, 144k² - 81 = (12k)²-(9)² = (12k - 9)(12k + 9)

If the area of a square is given by the expression 64k² - 112k + 49, then what will be its side?

• (8k + 7)

• (8k - 7)²

• (8k + 7)²

• (8k - 7)

Answer explanation

By using identity (a - b)²= a² - 2ab + b² and, taking a = 8k, b = 7, 2ab = 2(8k)(7) 64k² - 112k + 49 = (8k - 7)² Since the area of a square = side² and area of square = 64k² - 112k + 49 = (8k - 7)² Therefore, the side of the square = 8k - 7 So, option 4 is correct.