Factor and evaluate: 21 x 2.3 - 21 x 1.3

Question

This is a question on my math homework. I know how to factor but this factoring and evaluating is confusing.

Answer 1

Abbi, as Arthur showed you, this is the opposite of the distributive property.

 

Remember that x(y + z) = xy + xz. Normally, we would do the parentheses first if we had 5(4 + 6) = 5(10) = 50, but we can also do 5 x4 + 5 x 6 = 20 + 30 = 50. Your problem is this backward!

Answer 2

21x2.3-21x1.3

factor out 21

21(2.3-1.3)

21(1)

21 is the answer

check:21x2.3-21x1.3=48.3-27.3=21