Question

Twice Jack's age plus 5 is 21. Write and solve an equation. How old is Jack?

Answer 1

Well set up an equation again:
2x + 5 = 21

Solve for x now.

Answer 2

jack can be 8 because once you multiply that by 2 you get 16 and 16 plus 5 is 21 (:

Answer 3

in that's exactly what you have in the equation lol , just saw that. @calculusxy

Answer 4

Yes.
Look at the equation:
2x + 5 = 21
21 - 5 = 16
2x = 16
Divide both sides by 2
16/2=8
x = 8

Proof:
2(8)=16 + 5 = 21