How to factor (y-3)(y+4)=30
\((y-3)(y+4)= 30\) then you have \(y^2+4y-3y-12=30\) ⇔ \(y^2+y-42=0\) ⇔ \((y+7)(y-6)=0\)
so first you expanduse foil or whatevery²-3y+4y-12=30y²+y-12=30minus 30 from both sidesy²+1y-42=0factorwhat 2 numbers multiply to -42 and add to 1?-6 andn 7(y-6)(y+7)=0set each to zeroy-6=0y=6y+7=0y=-7y=-7 or 6
