Question

If a = 7, what is the value of the expression 2(a + 8)?

Answer 1

2 ( 7 + 8 )

Do the distribute property.

14 + 16

= 30

Answer 2

Plug in a=7, and you have 

2( 7 + 8 )

Here, we know that 7+8=15

So we have 2( 7 + 8 ) = 2( 15 )

2 times 15 equals 30

So 2( 7 + 8 ) = 2( 15 ) = 30