Tìm x biết: (x + 9) + (x – 2) + (x + 7) + (x − 4) + (x + 5) + (x − 6) + (x + 3) + (x – 8) + (x + 1) = 95
Giải thích
(x + 9) + (x – 2) + (x + 7) + (x − 4) + (x + 5) + (x − 6) + (x + 3) + (x – 8) + (x + 1) = 95
x × 9 + (9 + 7 + 5 + 3 + 1 – 2 – 4 – 6 – 8) = 95
x × 9 + 5 = 95
x × 9 = 95 – 5
x × 9 = 90
x = 90 : 9
x = 10