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-3x+2y=-39 and 5x+4y=21

User Heldt
by
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2 Answers

5 votes

Answer:

-3x+2y=-39

2y=-39+3x

y=-39+3x÷2 equation 1

5x+4y=21 equation 2

5x+4(-39+3x)÷2=21

5x+2(-39+3x)=21

5x+(-78)+6x=21

5x-78+6x=21

5x+6x-78=21

11x-78=21

11x=21+78

11x=99

x=99÷11

x=9

putting value of equation 2 in equation 1

y=-39+3x÷2

y=-39+3×9÷2

y=-39+27÷2

y=-12÷2

y=-6

x=9 and y=-6 answer

hope this may help you !!!!

User Thina
by
5.3k points
5 votes

Answer:

X= 9

Y = -6

Explanation:

first of all setting up the equation and solve it like a system of linear equations

5x+4y=21

-3x+2y=-39

then multiply -2 on the entire second equation

5x+4y = 21

6x-4y= 78

then eliminate the 4ys and you get

11x = 99

x = 9

lastly subsititue the 9 back into one of the original equations

5(9) + 4y =21

45 + 4y = 21

4y = -24

y = -6

User Deathemperor
by
5.8k points