Question

aflati numarul a din egalitatea urmatoare:
{[(5a+23):17+18}× 5+20}:8=72-3×4.

Answer 1

{[(5a+23):17+18]x5+20}:8=72-3x4
{[(5a+23):17+18]x5+20}:8=72-12
{[(5a+23):17+18]x5+20}:8=60
{[(5a+23):17+18]×5+20}=60x8
[(5a+23):17+18]×5+20=480
[(5a+23):27+18]x5=480-20
[(5a+23):17+18]x5=460
(5a+23):17+18=460:5
(5a+23):17+18=92
(5a+23):17=92-18
(5a+23):17=74
5a+23=74x17
5a+23=1258
5a=1258-23
5a=1235
a=1235:5
a=247

Answer 2

Rezolvăm pe părți:
(5a + 23):17 + 18 = 5a/17 + 23/17 + 18 = 5a/17 + 329/17;
(5a/17 + 329/17)x5 = 25a/17 + 1645/17;
(25a/17 + 1645/17) + 20 = 25a/17 + 1645/17 + 340/17 = 25a/17 + 1985/17;
(25a/17 + 1985/17):8
72 - 3x4 = 72 -12 = 60;
(25a/17 + 1985/17):8 = 60;
25a/17 + 1985/17 = 480;
25a + 1985  = 480x17;
25a = 8160 - 1985;
25a = 6175;
a = 6175:25;
a = 247