Step-by-Step explanation:
so first we define x in terms of p (or p in terms of x)
x=180-p
replace x in the equation x+20=p with 180-p
180-p+20=p
add p to each side
200=2p
p=100
so now we can find x
180-p=x
180-100=x
x=80
say z=?
7=80/z
multiply both sides by z
7z=80
divide both sides by 7
z=80/7
?=11 3/7
