How do you foil #(y-4)(y+5)#?

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Answer 1 · 2015-09-02T17:14:34

#(y-4)(y+5) = color(blue)(y^2+y-20)#

The expression is :# (y−4)(y+5)#

F O I L involves carrying out the below operations in the following order:

1) product of First terms :#(color(blue)(y and y))#+

2)product of Outside terms:#(color(blue)(y and 5))#+

3)product of Inside terms:#(color(blue)(-4 and y))#+

4)product of Last terms:#(color(blue)(-4 and 5))#

1) #y*y=color(blue)(y^2) +#

2) #y* 5=color(blue)(5y)+#

3) #-4 * y = color(blue)(-4y)+#

4) #-4 *5 = color(blue)(-20#

adding all the terms

#=color(blue)(y^2+5y-4y+(-20)#
#=color(blue)(y^2+y-20)#