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Valentin [98]
3 years ago
15

Which of these strategies would eliminate a variable

Mathematics
2 answers:
sdas [7]3 years ago
8 0

Answer:

Multiply the first equation by 3

Multiply the second equation by -7

Step-by-step explanation:

After doing the above method, you will derive equation 3 and 4 then you can eliminate the x and get y .

FURTHER EXPLANATION

-7x + 2y = 5 -------(1)\\3x - 5y = -5-------(2)\\\\-7x + 2y = 5 -------(1) \times 3\\3x - 5y = -5-------(2)\times-7\\\\-21x +6y=15 -----(3)\\-21x +35y=35----(4)\\Subtract -eq- 4- from -eq- 3 \\-29y =-20\\Divide-both-sides-by;-29\\\frac{-29y}{-29} =\frac{-20}{-29} \\y = 20/29\\

Substitute ; 20/29 for  y- in- eq 1\\-7x + 2y = 5----(1)\\-7x +2(20/29) = 5\\-7x +40/29=5\\-7x = 5 - 40/29\\-7x = 105/29\\Divide through by -7\\x = -15/29

I Hope It helps

katen-ka-za [31]3 years ago
7 0

Answer:

Multiply the first equation by 3

Multiply the second equation by -7

Step-by-step explanation:

( - 7x + 2y = 5) \times 3 \\ (3x - 5y =  - 5) \times 7

- 21x + 6y = 15 ..(3)\\  - 21x - 35y =  - 35...(4)

Subtract equation 3 from equation 4

- 21x - ( - 21x) =  - 21x + 21x = 0

x has been eliminated

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