Answer
$a=-3, $
$b=-1$
Work Step by Step
Apply Theorem 4.6, Additive lnterval Property
on the first two integrals on the LHS:
$\displaystyle \int_{-3}^{3}f(x)dx+\int_{3}^{6}f(x)dx=\int_{-3}^{6}f(x)dx$
For the third integral on the LHS, apply
Special Definite lntegrals : $\displaystyle \int_{b}^{a}f(x)dx=-\int_{a}^{b}f(x)dx$.
$LHS=\displaystyle \int_{-3}^{6}f(x)dx+\int_{b}^{a}f(x)dx =\displaystyle \int_{b}^{a}f(x)dx+\int_{-3}^{6}f(x)dx$
If we set $a=-3, b=-1$
by the Additive lnterval Property, this will equal
$\displaystyle \int_{-1}^{6}f(x)dx=RHS$
