Question

how do i make x the subject of the formula with this equation. (x-1)(y+2)=3

Answer 1

to isolate x,see what is multiplied with it
so when u divide that on both sides,u can isolate x,
so what should be divided?

Answer 2

i've multiplied the brackets out and i've come up with xy+2x-y-2=3..so it would be divided by 2 or y?

Answer 3

ok,since u have already multiplied the brackets,now u don't need to divide anything.
Now u take all the terms which do not contain x on other side.
like here u have to take -y and -2 on other side,u know how u can do that??

Answer 4

i've tried to rearrange it.. xy+2x =3+y+2..i got this

Answer 5

correct :) now take x common from left side
from xy+2x
then what u get?
remember :
ab+ac=a(b+c)

Answer 6

oy thats alot of extra work ;)

Answer 7

yes,but as u can see, honeymonster has already multiplied the brackets.....

Answer 8

have him put them back together ... oh the humanity!

Answer 9

its almost done,taking common and then dividing it......

Answer 10

would you divide it by y+2?

Answer 11

to begin with, that would be a swell idea

Answer 12

\[(x-1)(y+2)=3~:~divide~by~(y+2)\]
\[\frac{(x-1)\cancel{(y+2)}}{\cancel{(y+2)}}=\frac{3}{(y+2)}\]
\[x-1=\frac{3}{(y+2)}\]

Answer 13

ok so then how do you get rid of the -1?

Answer 14

if you owe someone 1 dollar, how do you get to the point where you owe them nothing?

Answer 15

give it back..so you would add it to the otherside?

Answer 16

yes; add 1 to both sides

Answer 17

\[x-1+1=\frac{3}{(y+2)}+1\]
\[x-0=\frac{3}{(y+2)}+1\]
\[x=\frac{3}{(y+2)}+1\]

Answer 18

ok thats great! thank you for the help :)

Answer 19

youre welcome, it was a communal effort :)