Question

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

1. Isolate x in the first equation
2. Replace the x in the second equation with the expression for x isolated in the first equation.

Answer 2

its a ?

Answer 3

you have x=1+4y
putting this into 2x-9y=3 gives you
2(1+4y)-9y=3 <=> 2+8y-9y=3 <=> -y=1 <=> y=-1
Now put y into the first equation: x=1+4(-1)=1-4=-3
so you have (-3,-1)

Answer 4

ty i jus dont understand how u put the first equation into the second?

Answer 5

1st equation: x - 4y = 1
2nd equation: 2x - 9y = 3

1st equation (x isolated): x = 1 + 4y
2nd equation (x substituted): 2(1 + 4y) - 9 = 3