Blahhh
Jan 19, 2009, 01:59 PM
how do I solve this in steps
2x+3y=18
5x-y=11
galactus
Jan 20, 2009, 10:29 AM
Solve the bottom equation for y and sub into the top one. Then, the top one will be entirely in terms of x. Solve away.
ROLCAM
Jan 29, 2009, 05:51 PM
2x+3y=18
5x-y=11
Multiply the second equation by 3.
Eliminate the ys.
Add up the xs and equivalents
Then take it from there.
shatriya
Jan 30, 2009, 07:25 AM
how do i solve this in steps
2x+3y=18
5x-y=11
Basics of solving the equations is that you need to make any element same in both the equations.
Like,
2x+3y=18 ------> equation 1
and 5x-y=11 -----> equation 2
now you have to see that how can you make one element equal in both the equations.
either multiply eq 1 by 5 and eq 2 by 2
then the equation will become,
10x+15y=90 ------> equation 3
and 10x-2y=22 -----> equation 4
So we got 10x as common in both the equations
But this was a little hectic because we have to do a lot of multiplication, we are humans and we are supposed to make things easier.
So, multiply equation 2 by 3, that's it
then the equation will become,
2x+3y=18 ------> equation 3
15x-3y=33------> equation 4
So we got 3y as common.
Now, add eq 3 to eq 4,
where +3y will cancel -3y
we'll get,
17x=51 => x=51/17 => x=3
Put the value of x in either eq1 or eq 2 and get value of y