Question

21/[4+(13-x)*2+1]=25-(6*3+4)

Answer 1

21 = (5+(-x + 13)•2) • (-(18 + 4)) + (5 + (-x + 13) • 2) • 25
(4 + (13 - x) • 2 + 1) • 21 / 4 + (13 - x) • 2 + 1 = (4 + (13-x) • 2 +1) • 25 + (4 + (13 - x) • 2 +1) • (-(6•3+4))
(5 + (-x +13)•2) • (-(18+4)) + 5 + (-x + 13) • 2) • 15 = 21
(5 + -2x + 26) • (-22) + (5+ -2x + 26) • 25 = 21
(-2x + 31) • (-22) + (-2x + 31) • 25 = 21
21 / 4+(13-x) • 2 + 1 = 25 - (6•3+4)
22 • x - 682 + -25 • 2x + 775 = 21
44x - 50x + 93 = 21
x = 12.

Answer 2

Aceasta este varianta mai simpla a rezolvarii :)