22.....................

Answer:
a=11,b=7
Step-by-step explanation:
To get to the result we firs multiply the figures on the left hand side.
multiplication of each term with its similar term is shown:
5×-4=-20
x⁷ₓx⁴=x¹¹. Here we add the powers because we are multiplying indices to the same base.
y²ₓ y⁵= y⁷
Thus the correct answer is a=11 and b=7
Answer:
[tex]a=11,b=7[/tex]
Step-by-step explanation:
The given equation is
[tex](5x^7y^2)(-4x^4y^5)=-20x^ay^b[/tex]
Recall that [tex]a^m\times a^n =a^{m+n}[/tex]
We simplify the left hand side to obtain;
[tex]-20x^{7+4}y^{2+5}=-20x^ay^b[/tex]
This implies that;
[tex]-20x^{11}y^{7}=-20x^ay^b[/tex]
Comparing exponents, we have
a=11,b=7
The first choice is correct.