How do you solve $y = 3 x + 8$ $y= 3x+8$ and $y = 5 x - 10$ $y=5x-10$ using substitution?

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Answer 1 · 2016-03-09T13:56:07

The solution for the system of equations is:
$x = 9$ $color(green)(x=9$
$y = 35$ $color(green)(y=35$

$y = 3 x + 8$ $color(blue)(y=3x+8$ .....equation $(1)$ $(1)$

$y = 5 x - 10$ $y=5x−10$ ....equation $(2)$ $(2)$

Solving by substitution:
Substituting equation $(1)$ $(1)$ in $(2) :$ $(2):$

$y = 5 x - 10$ $y=5x−10$

$3 x + 8 = 5 x - 10$ $color(blue)(3x+8)=5x−10$

$8 + 10 = 5 x - 3 x$ $8+10=5x -3x$

$18 = 2 x$ $18=2x$

$x = \frac{18}{2}$ $x=18/2$

$x = 9$ $color(green)(x=9$

Finding $y$ $y$ from equation $(1) :$ $(1):$
$y = 3 x + 8$ $y=3x+8$

$y = 3 \times 9 + 8$ $y=3 xx 9+8$

$y = 27 + 8$ $y=27+8$

$y = 35$ $color(green)(y=35$

How do you solve y=3x+8y= 3x+8 and y=5x−10y=5x-10 using substitution?