1. x + 3 (x + 4) = 20

x + 3 (x + 4) = 20

Multiply the bracket by 3

(3) (x) (3) (4) = 3x+12

x+3x+12=20

4x+12=20

Move + 12 to the other side. Sign changes from + 12 to - 12.

4x+12-12=20-12

4x=8

Divide by 4 for both sides.

4x/4=8/4

Cross out 4 and 4, divide by 4 and then becomes x

x=2

Answer: x=2

Answer: x = 2

Step-by-step explanation: Isolate the variable by dividing each side by factors that don't contain the variable.