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1 vote
3x + y = -1
2x + 3y = 18

User Bytesgo
by
7.6k points

1 Answer

4 votes

Answer:
x=-3\\y=8

Explanation:


3x+y=-1\\2x+3y=18

Multiply by -3 the upper equation to make y equal in value but with opposite signs.


(-3)(3x+y=-1)\\-9x-3y=3

Now add equation 1 and 2.


-9x-3y=3\\2x+3y=18

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


-7x=21

Solve for x;

To isolate x, divide by -7


(-7x)/(-7)=(21)/(-7)


x=-3

Now use one of the equations above and replace the value of x.


3x+y=-1\\3(-3)+y=-1\\-9+y=-1\\y=-1+9\\y=8

To prove if it's correct, take either equation and replace both x and y values, if the results are equal to each other, it is correct.


2x+3y=18\\2(-3)+3(8)=18\\-6+24=18\\18=18

User Richzilla
by
6.8k points