Question

Sindhu successfully solved the system of equations 3x+y=9
and −2x−y=−7
. Which of these statements could correctly describe what she did?
A
She added the two equations together to solve for x, and then she substituted the value of x back into one of the equations and solved for y, getting x = 2 and y = 3.

B
She added the two equations together to solve for x, and then she substituted the value of x back into one of the equations and solved for y, getting x = 3 and y = 2.

C
She added the two equations together to solve for y, and then she substituted the value of y back into one of the equations and solved for x, getting x = 2 and y = 3.

D
She added the two equations together to solve for y, and then she substituted the value of y back into one of the equations and solved for x, getting x = 3 and y = 2.

Answer 1

A. She added the two equations together to solve for x, and then she substituted the value of x back into one of the equations and solved for y, getting =2x=2 and =3y=3.

Answer 2

its d This option states that she added the two equations together to solve for y, which would eliminate x. This is correct. Then she substituted the value of y back into one of the equations and solved for x, which is the correct method. The solution states x = 3 and y = 2

Answer 3

It's A.

By adding the two equations the result is:
\[
(3x+y) + (-2x-y) = (9) + (-7) \\
3x - 2x + y-y = 9 - 7 \\
x = 2
\]

Substituting into one of the equations:
\[
3x + y = 9\\
3(2) + y = 9\\
6 + y = 9 \\
y = 9 - 6 \\
y = 3
\]