(x+5)(x-3)=9 I am not sure how to work this out?
2 answers
mutiply out the 2 factors and subrtract 91 from both side to equate equation to zero then solve for root
x^2+5x-3x-15=9
x^2+2x=9+15
x^2+2x=24
x^2+2x+1=24+1
(x+1)^2=25
Becouse: (x+1)^2=x^2+2x+1
x+1=sqroot(25)
x+1=5 and
x+1=-5
x+1=5
x=5-1=4
x+1=-5
x=-5-1=-6
Solutions is:
x=4 and x=-6
x^2+2x=9+15
x^2+2x=24
x^2+2x+1=24+1
(x+1)^2=25
Becouse: (x+1)^2=x^2+2x+1
x+1=sqroot(25)
x+1=5 and
x+1=-5
x+1=5
x=5-1=4
x+1=-5
x=-5-1=-6
Solutions is:
x=4 and x=-6