Answer
a). 7
b). 10
c). Addition
Work Step by Step
a). $b^{4}$.$b^{3}$ = (b.b.b.b)(b.b.b) = $b^{4+3}$ = $b^{7}$
b). $b^{5}$.$b^{5}$ = (b.b.b.b.b)(b.b.b.b.b) = $b^{5+5}$ = $b^{10}$
c). When exponential expressions are multiplyied the exponents will be added.
Example= $x^{5}$ $x^{6}$ $x^{7}$ = $x^{5+6+7}$ = $x^{18}$
