How do you solve x2−2x−8=0 by graphing?

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How do you solve  x2−2x−8=0  by graphing?

huglaus51 · Accepted Answer

Step 1Let&#039;s find the vertex first. We can find the x-coordinate by using x=−b2ax=−22×1=−22=1The y-coordinate can be found by plugging the x-value back into the equation:(1)2−2(1)−8=1−2−8=9The vertex is (1, 9). Next, let&#039;s find the x-intercepts, which are the zeroes of the equation. Let&#039;s factor the polynomial and find them:x2−2x−8=0(x−4)(x+2)=0x−4=0x=4x+2=0x=−2Step 2The x-intercepts are (4, 0) and (−2, 0). Finally, the y-intercept can be found by letting x=0:02−2(0)−8=−8The y-intercept is (0, −8). You can plot the bolded points, which will be able to create a decent outline of the parabola, If you need them, you can plot other points on the graph, such as (2, −8), (−1, −5), and (3, −5). This is what the graph will look like:Graph: {x2−2x−8[−9, 11, −10, 1]}

enguinhispi · Accepted Answer

Step 1  x2−2x−8=0  Solve with the quadratic formula  x1, 2=−(2)±(−2)2−4×1×(−8)2×1  (−2)2−4×1×(−8)=6  x1, 2=−(−2)±62×1  Separate the solutions  x1=−(−2)+62×1  x2=−(−2)−62×1  x=−(−2)+62×1=4  x=−(−2)−62×s1=−2  The solutions to the quadratic equationare:  x=4, x=−2

How do you solve x^{2}-2x-8=0 by graphing?

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