Answer:
a.) Vertical Angles
b.) Given (Parallel)
c.) Substitution
Step-by-step explanation:
You know

Squaring both sides gives

Then raising both sides to any integer power
gives

That is, any power of
where the power is a multiple of 4 will always be equal to 1.
So

But perhaps you mean to write 20+1 as the exponent, in which case

Answer:
-4x(5x-3)
Step-by-step explanation:
-20x^2 - 12x
-20x^2 = -4*5*x*x = -2*2*5*x*x
-12x = -4*3*x = -2*2*3*x
The common terms are -2*2*x = -4x. Whats left goes inside the parentheses
-4x(5x-3)
How would we do that here