Question

să se afle numarul natural x dacă
a)x+269=835
b)x-18=201
c)73-x=51
d)x+2x+3x....+20x=420​

Answer 1

Răspuns:

Explicație pas cu pas:

a)x+269=835

x = 835 - 269 = 566

b)x-18=201

x = 18 + 201 = 219

c)73-x=51

x = 73 - 51 = 22

d)x+2x+3x....+20x=420​

x(1 + 2 + 3 + ...+ 20) = 420

1 + 2 + 3 + ...+ 20 = 20*(1 + 20)/2 = 20*21/2 = 10*21 = 210

x*210 = 420

x = 420 : 210 = 2

Answer 2

a) x+269=835=

x=835-269

x=566

b)x-18=201

x=18+201

x=219

c)73-x=51

x=73-51

x=22