a.)
`a^2-25=color(red)((a-5)*(a+5))`

b.)
`b^2-100=color(red)((b-10)*(b+10))`

c.)
`9a^2-25b^2=color(red)((3a-5b)*(3a+5b))`

d.)
`16c^2-64=color(red)((4c+8)*(4c-8))`

e.)
`x^4-9=color(red)((x^2-3)*(x^2+3))`

f.)
`a^4-b^4=color(red)((a^2-b^2)*(a^2+b^2)`

g.)
`x^2+6x+9=color(red)((x+3)*(x+3))`

h.)
`a^2+10a+25=color(red)((a+5)*(a+5))`

i.)
`y^2-8y+16=color(red)((y-4)*(y-4))`

j.)
`z^2-12z+36=color(red)((z-6)*(z-6))`

k.)
`9a^2+12ab+4b^2=color(red)((3a+2b)*(3a+2b))`

l.)
`100x^2-20xy+y^2=color(red)((10x-y)*(10x-y))`





a.)
`-a-2b+4c=color(red)((-1)*(a+2b-4c))`

b.)
`3b^2-3a^2=color(red)((-3)*(a+b)*(a-b))`

c.)
`-x^3+3x^2+x=color(red)((-x)*(x^2-3x-1))`

d.)
`2a^2b-5ab^2-a^3=color(red)((-a)*(-2ab+5b^2+a^2))`