If (x-1).(x-1)=400 then x-5 = ?
A) 15 B) 14 C) -24 D) -25 E) -26
What is the rapid way to solve this problem?
A) 15 B) 14 C) -24 D) -25 E) -26
What is the rapid way to solve this problem?
Given: (x-1)(x-1)=400t4nothing wrote:If (x-1).(x-1)=400 then x-5 = ?
A) 15 B) 14 C) -24 D) -25 E) -26
What is the rapid way to solve this problem?
If (something)(something) =400 then something = 20 or -20
So x-1 = 20 or x-1 = -20
case 1: x-1=20 --> x=21 --> x-5=16 (not one of the answer choices)
case 2: x-1=-20 --> x=-19 --> x-5=-24 --> choose C
Cheers,
Brent
