Only one solution

Algebra Level 2

$x^{2} - mx + m - 1 = 0$

Find the value of $m$ when the above equation has only one solution.

The answer is 2.

1 solution

Abyoso Hapsoro
Apr 18, 2015

$D\quad =\quad 0$ ${ b }^{ 2 }\quad -\quad 4ac\quad =\quad 0$ ${ (-m) }^{ 2 }\quad -\quad 4(1)(m-1)\quad =\quad 0$ ${ m }^{ 2 }\quad -\quad 4m\quad +\quad 4\quad =\quad 0$ ${ (m\quad -\quad 2) }^{ 2 }\quad =\quad 0$ $m\quad -\quad 2\quad =\quad 0$ $m = 2$

Only one solution

The answer is 2.

1 solution

0 pending reports