Now bring 17.2 to the left side by subtracting 17.2 to both sides (what you do on one side you must do to the other). Since 17.2 is being added on the right side, subtraction (the opposite of addition) will cancel it out (make it zero) from the right side and bring it over to the left side.
8.18 - 17.2 = 1.31x
-9.02 = 1.31x
Then divide 1.31 to both sides to isolate x. Since 1.31 is being multiplied by x, division (the opposite of multiplication) will cancel 1.31 out (in this case it will make 1.31 one) from the right side and bring it over to the left side.
You need to substitute your values of the variables into the y=mx+b. So.......
8.18=1.31x+17.2
next, you would solve like a linear equation. so, you would subtract 17.2 from each side first, which would give you
-9.02=1.31x
then, you would divide each side by 1.31. this would give you your answer
-6.885496=x
this varies on teacher, and should be specified in the instructions which place value you are to round to. i will round this to the 2nd decimal place, so
