Question

4X - 5Y = -18 , 5X + 4Y = -2

Answer 1

Solve for x in terms of y in one equation, then substitute that expression for x in second equation and solve for y. Plug the solution for y back into you expression for x and solve for x. Check that your solution satisfies each equation!

Answer 2

4X - 5Y = -18.............1 multiply by 5
5X + 4Y = -2...............2 multiply by 4


20x-25y =90...................1
20x+16 y = -8...................2 multiply by -1

20x-25y =90...................1
-20x-16y=8.......................2

add equation 1 to equation 2
-41y=98
y=-2.39

sub value of y in any equation
4x-5(-2.39)=-18
x=-7.4875

you are welcome .

Answer 3

waleed made an error: 5 x equation 1 should be = -90, not 90. Sign was wrong. Good luck.

Answer 4

yeah .. you are right ! .... thnx ... I do mistake all time .. one day i will be better

4X - 5Y = -18.............1 multiply by 5
5X + 4Y = -2...............2 multiply by 4


20x-25y = - 90...................1
20x+16 y = -8...................2 multiply by -1

20x-25y = - 90...................1
-20x-16y = 8.......................2

add equation 1 to equation 2
-41y=-82
y = 2

sub value of y in any equation
4x-5(2)=-18
x=-2