Question

Question For the function f(x) = 8x2 - 18x + 5, use f(x) = -4 to find two points that lie on the graph of the function.answer format(__,__) , (__,__)

Answer 1

To find the points that fullfil the equation:

`f(x)=-4`

we plug the expression for the function and solve for x, then:

`\begin{gathered} 8x^2-18x+5=-4 \\ 8x^2-18x+9=0 \\ x=\frac{-(-18)\pm\sqrt[]{(-18)^2-4(8)(9)}}{2(8)} \\ x=\frac{18\pm\sqrt[]{324-288}}{16} \\ x=\frac{18\pm\sqrt[]{36}}{16} \\ x=(18\pm6)/(16) \\ x_1=(18+6)/(16)=(24)/(16)=(3)/(2) \\ x_2=(18-6)/(16)=(12)/(16)=(3)/(4) \end{gathered}`

Therefore the points are (3/2,-4) and (3/4,-4).