Wednesday

April 1, 2015

April 1, 2015

Posted by **Sarah** on Tuesday, January 18, 2011 at 6:09pm.

5x=4y-30

2x+3y+-12

- Math -
**helper**, Tuesday, January 18, 2011 at 6:49pm5x = 4y - 30

2x + 3y +-12

(1) 5x - 4y = -30

(2) 2x + 3y = 12

multiply (1) by 3(5x - 4y = -30)

(1) 15x + 12y = -90

multiply (2) by 4(2x + 3y = 12)

(2) 8x + 12y = 48

ADD two new equations

(1) 15x + 12y = -90

(2) 8x + 12y = 48

23x + 0 = -42

23x = -42

x = -42/23

substitute x = -42/23 in 2x + 3y = 12

to find y

(2) 2x + 3y = 12

2(-42/23) + 3y = 12

-84/23 + 3y = 12

3y = 12 + 84/23

3y = 276/23 + 84/23

3y = 360/23

y = 360/23 * 1/3

y = 360/69

y = 120/23

x = -42/23,

y = 120/23

**Answer this Question**

**Related Questions**

Math - use linear combinations to solve the system of linear equations. 2x+y=4 x...

math - PLEASE!!!!i need help on these 4: *4y=15-3x 2y=3x+21 *4x=5y-14 y=-6x-9 *...

math - PLEASE!!!!i need help on these 4: *4y=15-3x 2y=3x+21 *4x=5y-14 y=-6x-9 *...

math - i only need help on these two: *2/3y=10+4x 5x=1/3y-8 *5x=4y-30 2x+3y=-12 ...

Algebra HELP - USE LINEAR COMBINATIONS TO SOLVE THE SYSTEM OF LINEAR EQUATIONS (...

maths - use the substitution method to solve the linear system. 1. 3x=9 -x+2y=9 ...

linear algebra - Use an inverse matrix to solve each system of linear equations...

linear algebra - Use an inverse matrix to solve each system of linear equations...

linear algebra - Use an inverse matrix to solve each system of linear equations...

Discrete Math - True or False? Homogeneous linear recurrence equations are ...