Question

(ii) Determine whether the values given against the quadratic equation are the
to roots of the equation or not.
x2 + 4x - 5 = 0. x=1, - 1.​

Answer 1

Step-by-step explanation:

${x}^{2} + 4x - 5 = 0 \\ \\ putting \: the \: value \: of \: x = 1 \\ \\ {1}^{2} + 4 \times 1 - 5 = 0 \\ \\ 1 + 4 - 5 = 0 \\ \\ 5 - 5 = 0 \\ \\ 0 = 0 \\ \\ therefore \: 1 \: is \: the \: root \: of \: the \: quadratic \: eq. \\ \\ {x}^{2} + 4x - 5 = 0 \\ \\ putting \: the \: value \: of \: x = - 1 \\ \\ {( - 1)}^{2} + 4 \times ( - 1) - 5 = 0 \\ \\ 1 - 4 - 5 = 0 \\ \\ - 8 = 0 \\ \\ therefore \: - 1 \: is \: not \: the \: root \: of \: the \: eq.$