Related Formula
X² = |X|²$X^2 = |X|^2$
Quadratic factorization: t² - 5t + 6 = (t-2)(t-3)$t^2 - 5t + 6 = (t-2)(t-3)$
Core Logic
Rewrite the equation taking |x - 1| = t$|x - 1| = t$, where t ≥ 0$t \geq 0$.
Since (x-1)² = |x-1|²$(x-1)^2 = |x-1|^2$, the equation becomes:
t² - 5t + 6 = 0$$t^2 - 5t + 6 = 0$$
Step 1: Solve for modulus
(t - 2)(t - 3) = 0 ⇒ t = 2, 3$$(t - 2)(t - 3) = 0 \Rightarrow t = 2, 3$$
Since both roots are positive, both provide valid solutions for the modulus.
|x - 1| = 2 and |x - 1| = 3$|x - 1| = 2 \quad \text{and} \quad |x - 1| = 3$
Step 2: Unpack x values
From |x - 1| = 2$|x - 1| = 2$:
x - 1 = 2 ⇒ x = 3$$x - 1 = 2 \Rightarrow x = 3$$
x - 1 = -2 ⇒ x = -1$$x - 1 = -2 \Rightarrow x = -1$$
From |x - 1| = 3$|x - 1| = 3$:
x - 1 = 3 ⇒ x = 4$$x - 1 = 3 \Rightarrow x = 4$$
x - 1 = -3 ⇒ x = -2$$x - 1 = -3 \Rightarrow x = -2$$
The roots are 3, -1, 4, -2$3, -1, 4, -2$.
Step 3: Sum of Roots
Sum = 3 + (-1) + 4 + (-2) = 4$$\text{Sum} = 3 + (-1) + 4 + (-2) = 4$$
Pattern Recognition
In symmetric modulus equations f(|x-a|) = 0$f(|x-a|) = 0$, every valid root t$t$ generates twin solutions (a+t)$(a+t)$ and (a-t)$(a-t)$. The sum of each pair is perfectly 2a$2a$. If there are n$n$ distinct valid positive roots for t$t$, the sum of all x$x$-roots is exactly n × 2a$n \times 2a$. Here, n=2, a=1 ⇒ 2 × 2(1) = 4$n=2, a=1 \Rightarrow 2 \times 2(1) = 4$.
Chapter Mix
Class 11 Maths: Quadratic Equations