Question

Sindhu successfully solved the system of equations

3x + y = 9 and
- 2x - y = -7
Which of these statements could correctly descirbe what she did?

*optional but explain what makes it correct

Answer 1

Explanation:

when we add the 2 equations

3x + y = 9

-2x - y = -7

-------------------

x + 0 = 2

we see, x = 2. as we solved for x.

then using this e.g. in the first equation

3×2 + y = 9

6 + y = 9

y = 3

so, the first answer is correct.