Question

[6.02] Use the Substitution Method to solve the following system of equations.
x - 4y = 1
2x - 9y = 3

(-1, -3)

(-3, 1)

(3, 1)

(-3, -1)

Answer 1

solve for x:
x=1+4y
now put x into the second equation:
2(1+4y)-9y=3
2+8y-9y=3
-y = 1
y = -1
given your options, it must be D. But you would get x by plugging in -1 for y in the first equation:
x-4(-1) = 1
x+4=1
x = -3