2x +3y = 5

x² +3xy = 4

Okay, so I substitutey = -2/3x +5/3

x² +3x(-2/3x +5/3) -4I get '

3x² +5x -4'

It doesn't factorise, so I use the formula and answers are decimals, but the answers in textbook are1,1and4,-1So, what did I do wrong?