Answer:
6
Step-by-step explanation:
57=15+7x --> 57-15=7x --> 42=7x --> 42/7=x --> 6
It all depends on the math question but usually you solve for x, then check it. Plug x back in and see if it works. But it all depends on the math problem
(-4n^(2))* (5n^(7)):-20n to the power of 9
(2x)^(3)*(5x^(4 ))^(2): 200x to the power of 11