Intro to Pre-Algebra

 $5\left(4k\ +\ 9\right)$  

• 20k + 45

• 20k + 9

• 45k + 59

• 65k

Answer explanation

5(4k) = 20k
5(9) = 45

20k + 45

-4(2x + 7)

• -8x - 28

• 8x + 28

• -8x + 28

• -20x

Answer explanation

-4(2x) = -8x

-4(7) = -28

-8x - 28

9x(2y + 4)

• 18xy + 36x

• 18x + 36

• 92xy + 94x

• 54xy

Answer explanation

9x(2y) = 18xy

9x(4) = 36x

18xy + 36x

Which expression is equivalent to 20y + 8?

• 4(5y + 2)

• 20(y +8)

• 5(4y + 8)

• 8(20y+ 1)

Answer explanation

4 is divisible by both 20x and 8, so use that as the number to distribute. Then divide both numbers by 4 to get your numbers inside the parentheses.

$\frac{20y}{4}=5y$
$\frac{8}{4}=2$

so, 4(5y + 2) is equivalent (equal)

Which expression is equivalent to 23x + 11y + 18x?

• 52x

• 34x + 18y

• 23x + 29y

• 41x + 11y

Answer explanation

Combine 23x and 18x since they are like terms. Then re-write your expression.

23x+18x= 41x

41x + 11y

Choose all the expressions that are equivalent to 5ab + 3ab - 6b.

• 2ab

• 14ab

• 8ab - 6b

• b(5a + 3a -6)

• b(8a - 6)

Answer explanation

Three expressions are equivalent to the expression.

Rewrite the expression 12x(y - 3z)

• 12xy - 36xz

• 12xy - 12xz

• 12xy-9xz

• 12xy-3xz

Answer explanation

12x(y) = 12xy

12x (3z) = 36xz

12xy + 36xz

Which expression IS NOT EQUIVALENT to 5x -15?

• -5(-x+3)

• 5(x-3)

• 5(-x-3)

• -(-5x+3)

• 5(-x-3)

Answer explanation

5(-x-3) is not equivalent because:

5(-x) = -5x

5(-3) =-15

so, since 5(-x) = -5x, it isn't equivalent to the expression.