7.4

JOSH SugarLips MORALES __//**7.4**//__ Find the least common multiple between the X's or Y's. Multiply everything to get the top and bottom equation with one same variable. then add the top and bottom; you'll get one final equation, then solve for x or y. X=4 Y= -1

6x+5y=19 6(4)+ 5(-1)=19 19=19

Problem 2: X=2 Y=-1

10x+10y=10

Meredith Martin


 * __7.4__**


 * __Main Ideas__**

__N__either variable can be eliminated by adding or subtracting the equations. For systems like these, you can multiply one or both of the equations. For systems like the ones below, you can multiply one or both of the equations by a constants that adding or subtracting the equations will eliminate one variable.

Problem #2 6x + 5y = 19 2x + 3y = 5

2x + 3y = 5 2x + 3(-1) = 5 2x + (-3) = 5 2x = 8 x = 4

6x + 5y =19 -6x -9y = -15 -4y = 4 y = -1

Problem #2

4x + 5y = 35 2y = 3x - 9

Aly Surita Find the least common multiple between the X's or Y's. Multiply everything to get the top and bottom equation with one same variable. then add the top and bottom; you'll get one final equation, then solve for x or y.

Problem #1

6x-2y=1 18x-6y=3 -2x+3y= -5 -4x+6y = -10

14x= -7 x= -2 -2x+3y= -5 -2(-2)+3y= -5 -4 + 3y = -5

3y=-9 y= -3 x= -2

Problem # 2

6x+5y=19 6x + 5y = 19 2x+3y=5 -6x - 9y = -15

-4y = 4 y = -1

Trip Slaymaker, period 7.

7.4 SOLVING LINEAR SYSTEMS BY MULTIPLYNG FIRST- MAIN IDEA: In the case that no variables are eliminated from adding or subtracting the equations, multiply one or both of the equations by a constant so that the variable will be eliminated when the equations are added or subtracted. After this, you must use the new equation to solve for the variables (X and Y). Here's an example- 9x+3y=45 3x+4y=24

9x+3y=45 3(3x+4y=24)

9x+3y=45 __- (9x+12y=72)__ -9y=-27 __9y=27__ 9

y=3

9x+ 3X3 = 14

9x+9=14 -9 -9 9x=5 x=.6

Now try this on your own-

4x+3y=17 1x+4y=14
 * __workspace__**