A. A Parsec
A parsec is a unit of distance used to measure huge distances (as in solar system measurements)
Step-by-step explanation:
(x−1)²−9=0
(x-1)²= 9
x-1 = ±√9
x-1 = ±3
x = 1-3=-2 or x=1+3=4
the solution = {-2,4}
Sometimes it will, and sometimes it won't.
I reason as follows:
(21 + x) + (30 + 2x) = 51 + 3x has an 'x' term
(42 + x) + (30 - x) = 72 has no 'x' term.
Split it up
3x^2+12x-5x-20
group
(3x^2+12x)+(-5x-20)
factor
(3x)(x+4)+(-5)(x+4)
undistribute (x+4) like ab+ac=a(b+c)
(3x-5)(x+4)
