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What is the value of x in the solution to the system of equations below?

15x - 12y = 13

30x + 9y = 4

User Anooj VM
by
3.8k points

1 Answer

9 votes

Answer:

1/3

Explanation:

Use the elimination method.

15x - 12y = 13

30x + 9y = 4

If you add both equations you will not cancel out any variables, so you need to multiply one of the equations by something. Multiply the first equation by -2 to cancel out the x values.

-2(15x - 12y = 13)

30x + 9y = 4

You should have these two equations now:

-30x + 24y = -26

30x + 9y = 4

Add them together now. You should get this now.

33y = -22

Divide both sides by 33. You should get y = -2/3

Now, substitute the y value into any of the two equations that you started with. Let's substitute the y value for the second equation.

30x + 9 (-2/3) = 4

30x - 6 = 4

30x = 10

30 30 (divide 30 and 10 by 30)

x = 1/3

User Pavan Tiwari
by
4.2k points