2j+5=21
2j=16
j=8
<span>Jack is 8 years old.
</span>
Hope This Helped! :3
Answer:

Step-by-step explanation:
You can solve this equation with the quadratic formula which is:

All you need to do is rearrange the equation (add
to both sides and then multiply both sides by 2) to get:

From this new equation, we can easily see that a = 2, b = -5, and c = 11 AND you don't have to work with as many fractions. Substitute the values for a, b, and c into the quadratic formula to get:

That simplifies to:

Which simplifies even further to:

Which gets you:

P.S. The plus-minus sign wasn't working for me, so I had to just write, "+or-". I hope that didn't make it too confusing for you.
P.P.S. Hope this helps :) Don't forget to mark Brainliest if it did.
Answer:
8
Step-by-step explanation:
A/4 = 8/16
cross multiply
(16)(A) = (8)(4)
16A = 32
A = 32/16
A = 2
0.3 * (-(2 1/6))) + 0.35 = -0.3
That's how I got it.