208k views
0 votes
Factorise y to the power of 2 -y -72

1 Answer

1 vote

y^2-y-72=0\ \ \ | write\ -y\ as\ 8y-9y\\\\ y^2+8y-9y-72=0\\\\y(y+8)-9(y+8)=0\\\\(y-9)(y+8)=0\\\\ y=9\ or\ y=-8
User Masaaki
by
8.2k points