Find the value of x in the equation 2 x + 20 = 15 + 3 x .
a. 16
b. 1
c. –5
d. 25

The value of x is 5.

2x + 20 = 15 + 3x

Group like terms, change its signs.

2x - 3x = 15 - 20
-1x = -5
-1x/-1 = -5/-1
x = 5

To check: substitute x by its value. x = 5
2x + 20 = 15 + 3x
2(5) + 20 = 15 + 3(5)
10 + 20 = 15 + 15
30 = 30