Question

I have the linear equations: -4x-7y=5 and -3x-2y=11. I need to solve for x and y.

Answer 1

substitution or elimination ?

Answer 2

multiply the first equation by 3

multiply the second equation by 4
subtract the 2 new equations

This will give you an equqtion in y only - solve for y

puyt this VALUE of y into one of the original equations - this will give an equation in x only - solve for x...

Answer 3

-4x - 7y = 5 ---->(2)
-3x - 2y = 11 --->(-7)
--------------------
-8x - 14y = 10 (result of multiplying by 2)
21x + 14y = -77 (result of multiplying by -7)
--------------------add
13x = - 67
x = -67/13

now sub -67/13 in for x in either equation to find y
-3x - 2y = 11
-3(-67/13) - 2y = 11
201/13 - 2y = 11
-2y = 11 - 201/13
-2y = 143/13 - 201/13
-2y = - 58/13
y = (-58/13) / (-2)
y = -58/13 * - 1/2
y = 58/26 which reduces to 29/13

check...
-3x - 2y = 11
-3(-67/13) - 2(29/13) = 11
201/13 - 58/13 = 11
143/13 = 11
11 = 11 (correct)

so, x = -67/13 and y = 29/13.....or (-67/13, 29/13)