Verified answer

n! = 1*2*3*....*n

8!/7! = 1*2*3*4*5*6*7*8/1*2*3*4*5*6*7 = 8

если

7*8!+8*7!/8*8! = 7*8!+1/8

если

(7*8!+8*7!)/8*8! = 7!*(7*8+8)/8*8! = (56+8)/8*8 = 64/64 = 1

=(7*7!*8+8*7!)/8*7!*8=8*7!(7+1)/8*7!*8=(7+1)/8=1