5^ 10 1-5^ 100
=(5- 1)5^ 100
=4*5^ 100
=20*5^99
2.
3^20+3^ 19+3^ 18
=3^ 18(3^2+3^ 1+ 1)
= 13*3^ 18
3.
(x+2)(x-2)(x-7)(x-3)+ 10 1
=((x+2)(x-7))((x-2)(x-3))+ 10 1
=(x^2-5x - 14)(x^2-5x+6)+ 10 1
=(x^2-5x)^2 -8(x^2 -5x)+ 17
=(x^2 -5x-4)^2+ 1
& gt= 1