Y = -x + 4.....so sub in -x + 4 in for y in the other equation
x + 2y = -8
x + 2(-x + 4) = -8
x - 2x + 8 = -8
x - 2x = -8 - 8
-x = -16
x = 16
y = -x + 4
y = -16 + 4
y = - 12
one solution (16,-12)
On a number line, numbers always increase to the right and decrease to the left. Numbers to the right are greater than numbers to the left and numbers to the left are less than numbers to the right.
Remember, you can do anything to an equation as long as you do it to both sides
and when multiply or divide by a negative in inequalities, flip the direction of the sign
12x-39<9
add 39 to both sides
12x<48
divde bothh sides by 12
x<4
-4x+3<-6
minus 3 both sides
-4x<-9
times both sides by -1 and flip sign
4x>9
divide both sides by 4
x>9/4
