Answer:
E) (-4, -3)
Explanation:
To use elimination, you need to have one variable in both equations that have the same coefficient. (The coefficient is the number attached to the variable). Both equations have "7y".
The way elimination works is by eliminating one of the variables first. Decide how (-7y) and (-7y) can cancel out and become 0. You can either add or subtract.
(-7y) - (-7y) Try subtracting
= (-7y) + 7y
= 0
Based on this, we should subtract the whole equations.
Set up the equations like normal subtraction. Then, subtract each of the terms that have the same variable.
. 4x - 7y = 5
- 9x - 7y = -15 Do 4x - 9x = -5x. -7y - (-7y) = 0. 5 - (-15) = 20.
. -5x - 0 = 20 "y" cancelled out
. -5x = 20 Isolate 'x'
. -5x/-5 = 20/-5 Divide both sides by -5
. x = -4 Solved x-coordinate
Substitute 'x' for -4 in any of the equations. Then simplify and isolate "y" to solve for the y-coordinate.
4x - 7y = 5
4(-4) - 7y = 5 Simplify the multiplication.
-16 - 7y = 5 Start isolating 'y' now
-16 + 16 - 7y = 5 + 16 Add 16 to both sides. Left side cancels out 16
-7y = 5 + 16 Solved right side by adding
-7y = 21
-7y/-7 = 21/-7 Divide both sides by -7
y = -3 Solved y-coordinate
Therefore the answer is (-4, -3).