Twice jacks age plus five is 21. Write and solve an equation. How old is jack

Jack is 8

Step-by-step explanation:

j = jacks age

2j+5 = 21

This is the equation from Twice jacks age plus five is 21

We want to isolate j

Subtract 5 from each side

2j+5 = 21

2j+5-5 = 21-5

2j = 16

Divide by 2

2j/2 = 16/2

j = 8

Jack is 8 years old

Step-by-step explanation:

X2 + 5=21

21-5=16%2=8

Jack is 8 years old