Question

A student is trying to solve the system of two equations given below:

Equation P: y + z = 4
Equation Q: 3y + 7z = 15

Which of the following steps can be used to eliminate the y term?

−3(y + z = 4)
3(y + z = 4)
−1(3y + 7z = 15)
−3(3y + 7z = 15)

Answer 1

we have +1y and +3y

when we add them up, we get 4y when we want 0y instead

we can fix this by turning that +1y into -3y since -3y + 3y = 0y

Answer 2

remember that multiplying that 1y by -3 means you have to multiply everything else by -3 as well

Answer 3

does that make sense?

Answer 4

I think I may understand

Answer 5

so which answer choice do you think it is?

Answer 6

c ?