Solve the system using elimination.

-10x - 3y = - 18

-7x - 8y = 11

A) (-4, 3)

B) (3, - 4)

C) (2, - 1)

D) (-7, - 10)

We can't eliminate as is so we have to change something up there in the equations to get either the x values the same number but opposite signs, or the y values the same number but opposite signs. I chose to change the y values to the same number but different signs. In the first equation y is - 3y and in the second one, y is - 8y. The LCM of both of those numbers is 24, so we will multiply the first equation by an 8 (8*3=24) and the second equation by 3 (3*8=24) but since they are both negative right now, one of those multiplications has to involve a negative because - * - = +. Set it up like this:

8 (-10x - 3y = - 18)

-3 (-7x - 8y = 11)

Multiply both of those all the way through to get new equations:

-80x - 24y = - 144

21x + 24y = - 33

Now the y's cancel each other out leaving only the x's:

-59x = - 177 and x = 3. Now plug that 3 into either one of the original equations to find the y value. Either equation will work; you'll get the same answer using either one. Promise. - 7 (3) - 8y = 11 gives a y value of - 4. so your solution is (3, - 4) or B above.