Q:

50 Points Please show graphSolve the equation by graphing. x^2+14x+45=0First, graph the associated parabola by plotting the vertex and four additional points, two on each side of the vertex.Then, use the graph to give the solution(s) to the equation.If there is more than one solution, separate them with commas.

Accepted Solution

A:
Answer:The solutions are x = -9 , x = -5Step-by-step explanation:* Lets find the vertex of the parabola- In the quadratic equation y = ax² + bx + c, the vertex of the parabola  is (h , k), where h = -b/2a and k = f(h)∵ The equation is y = x² + 14x + 45∴ a = 1 , b = 14 , c = 45∵ h = -b/2a∴ h = -14/2(1) = -14/2 = -7∴ The x-coordinate of the vertex of the parabola is -7- Lets find k∵ k = f(h)∵ h = -7- Substitute x by -7 in the equation ∴ k = (-7)² + 14(-7) + 45 = 49 - 98 + 45 = -4∴ The y-coordinate of the vertex point is -4∴ The vertex of the parabola is (-7 , -4)- Plot the point on the graph and then find two points before it and  another two points after it- Let x = -9 , -8 and -6 , -5∵ x = -9∴ y = (-9)² + 14(-9) + 45 = 81 - 126 + 45 = 0- Plot the point (-9 , 0)∵ x = -8∴ y = (-8)² + 14(-8) + 45 = 64 - 112 + 45 = -3- Plot the point (-8 , -3)∵ x = -6∴ y = (-6)² + 14(-6) + 45 = 36 - 84 + 45 = -3- Plot the point (-6 , -3)∵ x = -5∴ y = (-5)² + 14(-5) + 45 = 25 - 70 + 45 = 0- Plot the point (-5 , 0)* To solve the equation x² + 14x + 45 = 0 means find the value of   x when y = 0- The solution of the equation x² + 14x + 45 = 0 are the x-coordinates  of the intersection points of the parabola with the x-axis∵ The parabola intersects the x-axis at points (-9 , 0) and (-5 , 0)∴ The solutions of the equation are x = -9 and x = -5* The solutions are x = -9 , x = -5