I am really not understanding the substitution method. Can someone please explain it to me?
Example:
Y=4x-9
y= x-3
I would really appreciate it =]
Hello Lexifer.
You have to equations
Y=4x-9 (eq1)
y= x-3 (eq2)
You know y because of (eq2) and so you substitute it in (eq1), this leads to
x-3 = 4x-9 (eq2 in eq1)
and you solve it for x.
Back to the two equations
Y=4x-9 (eq1)
y= x-3 (eq2)
You can use a substitution for x, too.
solving (eq2) for x
x = y+3 (eq2' )
and substitute it in (eq1) for x
4(y+3)-9=y (eq2 in eq1)
[In (eq1) you write y+3 instead of x because of eq2' ]
now you need to solve this equation for y
Still any questions? Then let us know
Yours
Rapha