How do I solve this question?
9a + 7b = 30
8b + 5c = 11
-3a + 10c = 73

What do I eliminate first?

Question

How do I solve this question? 
9a + 7b = 30 
8b + 5c = 11
-3a + 10c = 73 

What do I eliminate first?

anonymous · Answer

And please give out a  explanation of what ur doing :)

jdoe0001 · Answer

hmmm, well... maybe I'm not looking ... much... but the elimination method didn't give me much

jdoe0001 · Answer

the substitution method may work though

jdoe0001 · Answer

are you supposed to use elimination?

anonymous · Answer

Sorry I just saw this I was doing another question

anonymous · Answer

I guess yea

john_es · Answer

I would elminate the third, is easier. Row1+3*Row3,

anonymous · Answer

I kind of did it and im not getting the 3rd point

anonymous · Answer

@john_es

john_es · Answer

Multiply the third row by 3,
9a + 7b = 30 
8b + 5c = 11 
-9a + 30c = 219
Sum the first and third row,
 9a + 7b = 30 
8b + 5c = 11 
7b+30c = 249
Now multiply the third by -8 and the second by 7, sum, and substitute the result in the third row,
9a+7b=30
8b+5c=11
-205c=-1915
Solve the last equation,
c=383/41
Do backsubstitution,
a=279/41
b=-183/41

anonymous · Answer

Thanx :)