Question

Find the solutions of the equation. x2 - 4x - 5 = 0 Question 3 options: x = 5 and x = 1 x = -5 and x = -1 x = 5 and x = -1 x = -5 and x = 1

Answer 1

One way is to factor, since it is equal to 0, you can set the factors equal to 0$x^2-4x-5=0$what 2 numbers multiply to get -5 and add to get -4?-5 and 1$(x-5)(x+1)=0$set each factor equal to 0
x-5=0x=5
x+1=0x=-1

x=-1 and 5

Answer 2

$\bf x^2\stackrel{1-5}{-4}x\stackrel{1\cdot -5}{-5}=0\implies (x+1)(x-5)=0\implies x= \begin{cases} -1\\ 5 \end{cases}$