Răspuns :
x + 99 = 99 + 99 + ... + 99 (Stim ca in partea dreapta sunt 99 de termeni, deci:)
x + 99 = 99 * 99 => x + 99 = 9801 => x = 9702
x + 99 = 99 * 99 => x + 99 = 9801 => x = 9702
x+99=99+99+...+99
x+99=99·1+99·1+...+99·1
x+99=99·(1+1+...+1)
x+99=99·1·99
x =99·99 - 99
x =99·99 - 99·1
x =99·(99 - 1)
x = 99·98
x = 9 702
x+99=99·1+99·1+...+99·1
x+99=99·(1+1+...+1)
x+99=99·1·99
x =99·99 - 99
x =99·99 - 99·1
x =99·(99 - 1)
x = 99·98
x = 9 702