First we need to define our conditions. Since the angles are complimentary, the sum of the angles must be equal to 90 degrees.
let x = first angle
y = second angle
x + y = 90
from the second condition in the problem
x + y =72 + x -y
solving for x
x= 54
therefore the shorter side is 90 - 54 = y
y = 36 degree, the shorter side
For number 3.
You add 8 to both sides as you need to separate the variable
4x-8=32
+8 +8
4x=32
now divide 32 by 4
x=8
for number 4
you use pemdas to multiply the parenthisis
2(x-5)=-20
(2•x)-(2•5)
2x-10=-20
then add 10 to both sides
2x-10=-20
+10 +10
2x=10
divide 10 by two
x=5
Answer: ![(-9, 16]](https://tex.z-dn.net/?f=%28-9%2C%2016%5D)
This is the interval from -9 to 16. Exclude -9 but include 16.
=====================================================
Work Shown:
The idea is to multiply all sides by 5, then add 1 to all sides





This converts to the interval notation ![(-9, 16]](https://tex.z-dn.net/?f=%28-9%2C%2016%5D)
note: a curved parenthesis means "do not include this value in the solution set"; while a square bracket has us include the value. So we exclude -9 and include 16.