Have a question about a equation using a graph?

Question

Using a graph of y = x^2 + 4x - 5 to answer the following:
Using the graph, what are the solution(s) to the equation x^2 + 4x - 5 = 0 ? pleas explain your answers looking at a graph?

Does this function have a maximum or a minimum?
What are the coordinates of the vertex in (x, y) form?
What is the equation of the line of symmetry for this graph?


I know this is hard can anyone help please?

Answer 1

you can find the solution(s) to the equation by finding the two x intercepts on the graph.
(x-5)(x+1)=0, so they should be 5 or -1

The eq has a min because coeff of x^2 is positive.
vertex = (-b/2a, f(-b/2a)) = (-2, -9)
line of symmetry = x = -2

Answer 2

Norman has his signs wrong in the factoring of question 1. But to answer the question by looking at the graph, I assume you have a graphing calculator that you can see the graph--just find the x-values where the graph crosses the x-axis. Should be at -5 and 1

Answer 3

y = x^2 + 4x - 5
Function has a minimum becaus x^2 term is positive
The function factors to (x+5)( x-1) so the two roots arex = -5 and x - 1
The axis of symmetry is x = -b/2a = -4/2 = -2
The vertex lies on the axis symmetry so
y = (-2)^2+4(-2) -5 = -9
Thus vertex is at (-2,-9)