<span>Since it's even, the integral from -7 to -1 is the same as the integral from 1 to 7. </span><span>think about x^2
from 0..1,its 1/3
from 0..7 its 7^3/3
from -1..7 its 7^3/3+1/3 </span> <span>from -7..-1 of x^2 its -1/3+7^3/3 to get this without integrating we just do 7^3/3-1/3 which is the integral from 0..7 minus the integral from 0..1 </span><span>So the integral from 1 to 0 f(x) dx = 5 changes to the integral from 0 to 1 f(x) dx = -5 and you add it to the integral from 0 to 7 which is 1 making -4</span>
