If 5x+3y=12 and 4x-5y=17, what is the value of y?

y = -1

(and x = 3)

Step-by-step explanation:

5x + 3y = 12

4x - 5y = 17

First, we'll solve for x in terms of y

5x = 12 - 3y

x = 12/5 - 3/5y

x = 2.4 - 0.6y

Then substitute that mess into the next equation:

4(2.4 - 0.6y) - 5y = 17

and solve for a numerical value of y

9.6 - 2.4y - 5y = 17

-7.4y = 7.4

y = -1

To finish and check, we can use that to solve for x:

x = 2.4 - 0.6(-1)

x = 2.4 + 0.6

x = 3

And check both values in the original equations.

5x + 3y = 12

4x - 5y = 17

5(3) + 3(-1) = 15 - 3 = 12

4(3) - 5(-1) = 12 +5 = 17

LMK if you have questions.

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