Posted by **rany** on Sunday, March 15, 2009 at 11:00pm.

solve and comparison:

a)4x-9y=4

6x+15y=-13

im so lost!!!!!

- grade 9 math slope equations -
**Reiny**, Sunday, March 15, 2009 at 11:05pm
multiply the first by 3 to get

12x - 27y = 12 or 12x = 27y + 12

multiply the second by 2 to get

12x + 30y = -13 or 12x = -30y - 13

now "compare" the 12x of the first part with the 12x of the second part to get

27y + 12 = -30y - 13

etc.

"elimination" would be the more practical way of doing this one.

just subtract my two altered equations

- grade 9 math slope equations -
**rany**, Sunday, March 15, 2009 at 11:12pm
why do you hav to multiply it by three though?

- grade 9 math slope equations -
**Reiny**, Sunday, March 15, 2009 at 11:14pm
I wanted the x's to have the same coefficient.

you had

4x .... and

6x ....

think of finding a "common denominator"

and remember, what I do to one side of any equation, I must do to the other side.

- grade 9 math slope equations -
**rany**, Sunday, March 15, 2009 at 11:15pm
thank u so much !!!!!!

- grade 9 math slope equations -
**salsun**, Thursday, April 28, 2011 at 6:40am
i'm so dead!

- grade 9 math slope equations -
**Anonymous**, Wednesday, January 25, 2012 at 11:30am
Type the ordered pair that is the solution to these equations.3x - 2y = 8 2x + 5y = -1.

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