The answer for "-2a + 3b" is 5.
To solve this equation, you must first find "a" and "b". A^3 times B^2 = 72. In this case, a = 2 (2*2*2 = 8) and b = 3 (3*3 = 9) since their outcomes multiplied together equal 72.
Now you fill in for "a" and "b". "-2*2 + 3*3" before adding you do all the multiplying, which leaves "-4 + 9". Combining like terms gives you 5.
I hope this helps!!
