218k views
4 votes
​−8x+4y=24
−7x+7y=28​
x=?
y=?

1 Answer

2 votes

Answer:

  • x = -2
  • y = 2

Explanation:

You want the solution to the system of equations ...

  • -8x +4y = 24
  • -7x +7y = 28

Solution

We notice that each of these equations has a leading minus sign, and has coefficients that have a common factor. We can multiply by -1 to make the leading coefficient positive, and we can divide by the common factor. Doing this puts the equations in standard form:

2x -y = -6

x -y = -4

Subtracting the second equation from the first gives ...

(2x -y) -(x -y) = (-6) -(-4)

x = -2

Rearranging the second equation to find y, we have ...

y = x +4

y = -2 +4 = 2

The solution is (x, y) = (-2, 2).

<95141404393>

User David Taylor
by
3.5k points