Question

Solve using elimination
-3x+9y=12
2x-8y=-16

Answer 1

x=14 and y=6

Explanation:

-3x+9y=12.............(i)×2

2x-8y=-16..............(ii)×3

Multiplying equation (i) by 2 and equation (ii) by 3 and adding (i) and (ii)

-6x+18y=12

6x-24y=-48

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0-6y=-36

or, -6y=-36

So,y=6

From (i)

-3x+9y=12

or,-3x+9×6=12

or,-3x+54=12

or,-3x=12-54

or,-3x=-42

So,x=14

Answer 2

x=8 y=4

Explanation:

eliminate x: make x of two equation equal to each other

2(-3x+9y=12) : -6x+18y=24 ___[1]

-3(2x-8y=-16) : -6x+24y=48 ___[2]

[2]-[1]= 6y=24

y=4

substitute y to any equation;

2x-8y=-16

2x-8(4)= -16

2x= -16+32

2x= 16

x=8