How can we solve the simultaneous equations 3x−6y=−9 and 3x−4y=−13?

1 Answer
Shwetank Mauria
Feb 2, 2017

x=−7 and y=−2

Explanation:

The equations are

3x−6y=−9 ................................(1)

3x−4y=−13 ................................(2)

As we have 3x in both the equations, system of equations can be solved by eliminating this term, which can be done by subtracting equation (2) from (1). Doing this, we get

−6y−(−4y)=−9−(−13)

or −6y+4y=−9+13

or −2y=4 and y=−42=−2

Now putting this in (1), we get

3x−6×(−2)=−9

or 3x+12=−9

or 3x=−9−12=−21

i.e. x=−213=−7

Hence, x=−7 and y=−2

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