Systems and Equations Need Advise (Solve for X and Y)  TOPIC_SOLVED

Simplificatation, evaluation, linear equations, linear graphs, linear inequalities, basic word problems, etc.

Systems and Equations Need Advise (Solve for X and Y)

Postby isabelrachel on Sun Jun 21, 2009 3:55 pm

]Hello,

I need someone to tell me if i did this problem right.

The question asked is solve for x and y show all your work.

7x+3y=14,5x+9y=10
5x+9y=10

-3(7x+3y=14) ( times -3 times 7x times 3y times 14)

-21x-9y=-42 (Subtract -21 from 5x) (9y cancel's out) (subtract 42 from 10 )
5x=9y=10

-16x=-32
________(negative 16x and the one on the bottom both cancel out leaving you with just x then -16 divided by -32 is 2)
-16 -16

ANSWER x=2

NOW SOVE FOR Y

7(2)+3y=14
14+3y=14
_____________

( The 3y cancel out leaving you with just y and the 14 cancel out which would equal 0.)

ANSWER y=0


Are these correct?
isabelrachel
 
Posts: 9
Joined: Tue Jun 02, 2009 2:41 pm

Sponsor

Sponsor
 

  TOPIC_SOLVED

Postby stapel_eliz on Sun Jun 21, 2009 7:19 pm

You can check the answer to any "solving" problem by plugging it back in to the original question. In this case:

. . . . .7(2) + 3(0) = 14 + 0 = 14 (yes!)

. . . . .5(2) + 9(0) = 10 + 0 = 10 (yes!)

Your solution checks, so it must be right! :clap:
User avatar
stapel_eliz
 
Posts: 1713
Joined: Mon Dec 08, 2008 4:22 pm


Return to Beginning Algebra