Question

If (5x^4)(2x^6)=ax^b, what is the value of a-b?

Answer 1

$5x^4\cdot2x^6=ax^b\\10x^{10}=ax^b\\a=10 \wedge b=10$

$a-b=10-10=0$

Answer 2

$(5x^4)(2x^6)=(5\cdot2)(x^4\cdot x^6)=10x^{4+6}=10x^{10}=ax^b$

so

​$a=10\qquad b=10$

and

$a-b=10-10=\boxed{0}$