So Since we know what b equals. We can just plug it into the equation
b = 3
5a -10(3) = 45
First step is to solve -10(3) that means we multiply these two numbers.
-10 x 3 = -30
Now plug that in for what it was in the equation.
5a - 30 = 45
Now the next step is to add 30 to both sides to cancel out -30
5a - 30 = 45
+30 = +30
*************** Now the 30's on the left side disappear and we solve on the right side.
45 + 30 = 75
Now set up your equation once again.
5a = 75
Now we divide both sides by 5 to isolate (or get a to be alone)
5a = 75
÷5 = ÷5
********* the 5's on the left side disappear and we solve on the right side.
75 ÷ 5 = 15
So here's what we have left.
a = 15
Good Luck! :)
