Simultaneous Equations by Substitution

pruthive · 12-10-2014 08:31PM #1

hey all,
can someone help me to solve these equations by substitution method,

2x-3y-2=0 , 2x-3y-2 = 0

every time i did, i end up in a totally unbalanced numbers in both sides, and its not supposed to be. so anyone could help, it'll be great!

Cheers!

biko · 13-10-2014 06:40AM

From Blogs forum...

Delphi91 · 13-10-2014 08:56AM

You have a mistake there somewhere - both equations are the same!

pruthive · 13-10-2014 02:13PM

2x − 3y − 2 = 0, 3x + 8y − 3 = 0

sorry these are the two equations

dlouth15 · 13-10-2014 05:22PM

I would start with the first equation. Express it in the form y=... Then substitute the expression represented by ... into the second equation for y. You then have an equation in one variable, x. Simplify this and you get the answer for x. Then substitute this value for x into the first equation and simplify to get the answer for y.

Show your attempt so far then we can attempt to identify the mistake and point out the remedy.

Yakuza · 13-10-2014 05:30PM

Express x in terms of y:
Taking the first expression, you can rearrange it to read : 2x = 3y +2. Divide by 2 to get x=1.5y +1.

Now, substitute that into the second:
3x + 8y - 3 = 0 becomes
3(1.5y + 1) +8y - 3 = 0.
Expand this to get : 4.5y +3 + 8y -3 = 0
Gather the terms:
12.5y=0, so y=0.
If y = 0, then x is.....? (Left for the OP)

Simultaneous Equations by Substitution

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