Question

What is the value of x 0.4x + 3.9 = 5.78

Answer 1

0.4x + 3.9 = 5.78 Subtract 3.9 on both sides

0.4x + 3.9 - 3.9 = 5.78 - 3.9

0.4x = 1.88 Divide 0.4 on both sides

`(0.4x)/(0.4)=(1.88)/(0.4)`

x = 4.7

[proof]

0.4x + 3.9 = 5.78 Plug in 4.7 for "x"

0.4(4.7) + 3.9 = 5.78

1.88 + 3.9 = 5.78

5.78 = 5.78

Answer 2

x = 4.7

Explanation:

0.4x + 3.9 = 5.78

subtract 3.9 from each side

0.4x + 3.9-3.9 = 5.78-3.9

.4x = 1.88

divide by .4 on each side

.4x/.4 = 1.88/.4

x = 4.7