12.5
-5
5
X-5^2
5290
15
2n+5
x + 5
a variable is a letter used for a number that is unsolved like a+5=10 a would be 5
let x be the number, then: (x + 1) × 2 + 5 = x + 1 → 2x + 2 + 5 = x + 1 → 2x + 7 = x + 1 → 2x - x = 1 - 7 → x = -6 The number is -6. Checking: -6 +1 = -5; 5 × 2 = -10; -10 + 5 = -5 which is the same as -6 + 1 = -5.
6+n = 2n+5
whats REA number?whats REA number?