Respuesta :

tismian

Answer: x=7

               ab=21

               bc=14

Step-by-step explanation:

ab=3x

bc=2x±7

ac=42

3x±2x±7=42

5x±7=42

5x=42-7

5x=35

to get the value of x you divide 35 by 5x

35÷5x=7

so the value of x is 7

ab=3x

x=7

3x=7×3x

7×3=21

x=7

2x=7×2x

2×7=14