How do you solve by substitution $y = - 4 x + 8$ $y=-4x+8$ and $y = x + 7$ $y=x+7$ ?

Question

3727 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-03-26T20:26:17

$x = \frac{1}{5}$ $x = 1/5$

You have 2 expressions for y. $y = - 4 x + 8 and y = x + 7$ $y = -4x + 8 and y = x+7$ .

The second expression tells us that y is equal to $x + 7$ $x+7$ . Let's substitute $x + 7$ $x+7$ for the y in the first expression. That will give us

$x + 7 = - 4 x + 8$ $x+7 = -4x + 8$

And now, let's simplify.

$x + 4 x = 8 - 7$ $x+4x = 8 - 7$

$5 x = 1$ $5x = 1$

Therefore, $x = \frac{1}{5}$ $x = 1/5$ .

I hope this helps,
Steve

How do you solve by substitution y=-4x+8y=−4x+8y=-4x+8 and y=x+7y=x+7y=x+7?