Question

George starts with a number. He takes away 7, then squares it, adds 6, subtracts 13, multiplies it by 4 and subtracts 1. 


He ends up with 7. 


What was George’s original number? 

​

Answer 1

Answer:

10 or 4.

Step-by-step explanation:

[(x - 7)^2 + 6 - 13 ] * 4 - 1 = 7

(x^2 - 14x + 49 - 7) * 4 - 1 = 7

4x^2 - 56x  + 196 - 28  - 1 - 7 = 0

4x^2 - 56x + 160 = 0

4(x^2 - 14x + 40) = 0

(x - 10)(x - 4) = 0

x = 10 , 4