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