85 is the correct answer.
Take online tests on what you think you need work on
And also study
2x + y = 10 is y = -2x + 10
4x + 7 = 40
-7 -7
4x = 33
4 4
x = 8.25
y = -2(8.25) + 10
y = -6.5 and x = 8.25
Hope this helps :)

The Correct choices are :
<u>Question</u> 1 :
c. commutative property of multiplication
<u>Question</u> 2 :
d. commutative property of addition
<u>Question</u> 3 :
c.
, -0.4, 0.8,
, 