Question

solve by elimination:
4x + 9y = 28
-4x - y = -28
(7,0)
(6,0)
(-7,0)

Explanation:

Step1: Add the two equations

Add the equations \(4x + 9y = 28\) and \(-4x - y = -28\) together.

$$
LATEXBLOCK0
$$

Step2: Solve for y

Divide both sides of \(8y = 0\) by 8.

$$ y = \frac{0}{8} = 0 $$

Step3: Substitute y into one equation

Substitute \(y = 0\) into the first equation \(4x + 9y = 28\).

$$ 4x + 9(0) = 28\\ 4x = 28 $$

Step4: Solve for x

Divide both sides of \(4x = 28\) by 4.

$$ x = \frac{28}{4} = 7 $$

Answer:

(7, 0)