How do you solve the following system: $3 x + 4 y = 11, x - 3 y = 20$ $3x + 4y = 11 , x-3y=20$ ?

Question

2381 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-02-03T07:12:04

The solution for the system of equations is:
$y = - \frac{49}{13}$ $color(blue)(y = -49/13$

$x = \frac{113}{13}$ $color(blue)(x =113/13$

$3 x + 4 y = 11$ $color(blue)(3x) +4y =11$ .......equation $(1)$ $(1)$

$x - 3 y = 20$ $x -3y =20$ ,multiplying by $3$ $3$
$3 x - 9 y = 60$ $color(blue)(3x) -9y =60$ .......equation $(2)$ $(2)$

Solving by elimination

Subtracting equation $2$ $2$ from $1$ $1$

$cancelcolor(blue)(3x) +4y =11$
$-cancelcolor(blue)(3x) +9y =-60$

$13y = -49$

$color(blue)(y = -49/13$

Finding $x$ from equation $2$ :

$x -3y =20$

$x =20+3y$

$x =20+3 xx (-49/13)$

$x =20-147/13$

$x =260/13-147/13$

$color(blue)(x =113/13$

How do you solve the following system: 3x + 4y = 11 , x-3y=20 3x+4y=11,x−3y=203x + 4y = 11 , x-3y=20 ?