80.1 years, im not 100% sure of my answer though
<span>f '(x) = 2(3x2<span> + 5) + 6x(2x - 1)</span></span><span>= 6x2<span> + 10 + 12x</span>2<span> - 6x</span></span><span>= 18x2<span> - 6x + 10</span></span>
Answer: D
if correct pls give me a heart and mark brainleist as a thank you!
setup a simple algebraic equation and solve.
5x = 7x-28
-5x -5x
0=2x-28
+28 +28
28=2x
Now divide both sides by 2 and you get that she is 14
