What is the solution to this system? 3x+2y=45 4x+-y=5

asked Sep 15, 2021 230k views

5 votes

What is the solution to this system?
3x+2y=45
4x+-y=5

4.3k points

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4 votes

(I)
3x + 2y = 45

(II)
4x - y = 5

Get
alone in equation (II)

$4x - y = 5\\y = 4x - 5$

Insert new equation (II) in equation (I)

$3x + 2(4x - 5) = 45\\3x + 8x - 10 = 45\\3x + 8x = 45 + 10\\11x = 55\\x = 5$

Insert
x = 5 in equation (II)

$y = 4 \cdot 5 - 5\\y = 20 - 5\\y = 15$

Anson Horton answered Sep 20, 2021

4.6k points

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