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7 votes
7 votes
4x-3y=18 determine missing coordinate (?,-4)

User Marcelo Boeira
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1 Answer

21 votes
21 votes

Answer:

x = 1.5 (or as the fraction 3/2)

Explanation:

For this question, it is asking you to substitute numbers as variables using the coordinate pair given. (Important:) When looking at coordinates, the left number inside the parenthesis is the x-coordinate (? in this case), and the number in the parenthesis on the right is the y-coordinate (-4 in this case).

With that being said, this equation is basically asking us to solve for x. Now that we know this we can solve. Substitute y for -4:

4x - 3(-4) = 18

4x - (-12) = 18

When a negative sign is in front of a negative number, it becomes a positive number.

4x + 12 = 18

Now we can solve this problem using the proper formula. Subtract 12 from both sides of the equation to cancel out the +12:

4x + 12 = 18

- 12 -12

4x = 6

Now we need to single out the x in order to solve:

4x = 6

4 4

x = 1.5 (or simplified as the fraction 3/2)

Let me know if you need any more help with this topic, I hope that this helps.

User Ladislav Ondris
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2.9k points