Question

The question I need help with is this:Solve by graphing. 5x^2 + 8x -13a = 5, b = 8, and c = -13I get to the point where I think the axis of symmetry is -4/5. But, after that, I don't know how to figure out what to do.

Answer 1

Step 1:

In this question, we are to solve the quadratic equation using the graphical method:

`5x^2+8x\text{ -13 = 0}`

Step 2:

The line of symmetry is given as:

`\begin{gathered} x\text{= }(-b)/(2a) \\ \text{where a = 5 , b = 8} \\ x\text{ =}(-8)/(2(5)) \\ x\text{ =}(-8)/(10) \\ x\text{ = }(-4)/(5) \end{gathered}`

Step 3:

Now, the graph of the quadratic equation

`5x^2+\text{ 8 x - 13 = 0}`

and the line of the symmetry,

`x=(-4)/(5)`

is given as follows:

Part B:

For the y -coordinate of the vertex of the quadratic function:

`5x^2+8x-13\text{ =0}`

is as follows:

Hence, the vertex of the y-coordinate is:

`(-0.8,\text{ -16. 2)}`