The y-intercept is 100 and the slope is 5 write an equation that represent it's

y=5x+100

Step-by-step explanation:

equation of a line is y=mx+c

where m=slope c=y-intercept

You want to solve for 'z'.
First combine like terms on either side of the equal sign.

Left side:  9z +2  > No like terms, leave alone

Right side: 6z - 10 -z - 4  > circle like terms and add
                    6z -z = 5z
                   -10 -4 = -14
Now the equation is:
9z + 2 = 5z - 14

Get all the 'z' terms on the left side and all the numbers on right side.
You can move a term to the other side if you flip the sign.

Move 5z to left side, flip the sign to -5z
Move '2' to right side, flip the sign to -2

9z - 5z = -2 -14

Add like terms
4z = -16

Divide by 4 on both sides
z = -4