x-3y = -5 12x+3y = 8

Question

Solve the system of equations by elimination method or substitution method.

Answer 1

x - 3y = -5

12x + 3y = 8

This system is set up nicely to solve by elimination. Since we have opposite coefficients for y (-3 in the top and 3 in the bottom) we can add the two equations and eliminate the y.

x - 3y = -5

+ 12x + 3y = 8

13x = 3

Dividing we get x = 3/13.

Substitute this value of x into either equation and solve for y. I'll choose the first because it has smaller numbers.

(3/13) - 3y = -5 - Let's multiply both sides by 13 to eliminate the fractions.

3 - 39y = -65 - let's subtract 3 from both sides

-39y = -68 - let's divide both sides by -39

y = 68/39

Check the result by substituting x and y into BOTH equations.

Answer 2

Hi Michael P.

You can solve your equations by Elimination as follows:”

x - 3y = -5

12 + 3y = 8

Y is negative in the first equation above and positive to in the second equation it will “combine out” as -3y + 3y will give zero when you combine the two just as they are please try it.

You should be able to continue from here but if you have any questions please write back.

Answer 3

Add the two equations and solve for x.