I really need help with this one

28

Step-by-step explanation:

Since B is the midpoint of AC, that means AB = BC. That means 3x+4 = 5x-6. We can now set up an equation to solve for x:

3x+4 = 5x-6

3x+10 = 5x

10 = 2x

x = 5

Now that we know what x is, we can just plug x into the expression of AB and multiply it by 2:

(3*(5)+4)*2

=(15+4)*2

=19*2

=28

(side note: we could have plugged x into the expression of BC as well, but in this case plugging it into AB tends to be easier to solve)

Therefore, the length of AC is 28.

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x