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Find all points of intersections of the graphs of the equation
p(x)=(2x+3)(x-5)

User Mariza
by
3.3k points

1 Answer

4 votes

Answer:

The equation intersects the x or y axis a total ot three times:

(-1.5,0), (5,0), and (-15,0).

Explanation:

I will assume that the "all points of intersection" refers to the intersection of the line with the x and y axes. One can find those points by either a mathematical or graphing approach.

1) Mathematical

We and to find all points that have a zero for either the x or y coordinate: (0,y) and (x,0)

(x,0): Solve p(x)=(2x+3)(x-5) for p(x) = 0:

0=(2x+3)(x-5)

(2x+3)=0 and (x-5)=0

(2x+3)=0

2x=-3

x= - 1.5 (-1.5,0)

and

(x-5)=0

X=5 (5,0)

The two points marking the intersection with the x axis are (-1.5,0) and (5,0).

--

(0,y): Solve p(x)=(2x+3)(x-5) for p(x) for x=0:

p(x) = (2x+3)(x-5)

p(x) = (2*0+3)(0-5)

p(x) = (3)*(-5)

p(x) = -15 (-15,0)

The equation crosses the y axis at one point: (-15,0).

2. Graphing

See the attached graph. The points of intersection can be located, as shown. They match the values obtained mathematically, but a free graphing utility (DESMOS) makes graphing a pleasant chore.

Find all points of intersections of the graphs of the equation p(x)=(2x+3)(x-5)-example-1
User Enderskill
by
3.4k points