Question

Please answer !!! To solve the system of equations below, Luanne isolated the variable y in the first equation and then substituted it into the second equation what was the resulting equation ?

{2y=6x
{x²+y²=49
A. x²+9x²=49
B. x²+9x=49
C. x²+3x=49
D. x²+3x²=49

Answer 1

Option A. x² + 9x² = 49

Explanation:

Luanne used two equations given as 2y = 6x ------(1)

and x² + y² = 49 -----(2)

Luanne isolated the value of y from the equation 1 and then substituted in equation 2.

We will do the same.

from equation 1

2y = 6x

⇒ y = 3x

Now we plug in the value of y in equation 2.

x² + (3x)² = 49

x² + 9x² = 49

which matches the option A.