Question

write the equivalent equation that expresses y in terms of x. 2x+2x-y=3y and 2x(2-x)=x-y can someone please help with this..

Answer 1

For the first one:
You need to firstly collect the like terms.
\[2x+2x-y=3y\]
\[4x=3y+y\]
\[4x=4y\]

Then make y the subject to express y in terms of x.
\[4y=4x\]
\[y=4x/4\]
\[\therefore y=x\]

For the second one:
You need to expand the brackets.
\[2x(2-x)=x-y\]
\[4x-2x^2=x-y\]

Then get y by itself.
\[4x-2x^2+y=x\]
\[y=2x^2+x-4x\]

Finally collect the like terms.
\[\therefore y=2x^2-3x\]