Use the graphing calculator to graph the quadratic function y = 2x2 – 6x – 8. Which values are solutions of 0 = 2x2 – 6x – 8? Ch
2 answers:
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Answer:
x = 8
Step-by-step explanation:
A graphing calculator can show you the answer easily. It works well to define a function whose x-intercept is the solution. We can do that by subtracting 300 from the given equation so we have ...
F(2, x, 4, 11) -300 = 0
The solution is x = 8.
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We can solve this algebraically:
F(2, x, 4, 11) -300 = 0
2^x +4·11 -300 = 0 . . . . use the function definition
2^x -256 = 0 . . . . . . simplify
2^x = 2^8 . . . . . add 256
x = 8 . . . . . . . . . match exponents of the same base
For a given function, slope is defined as the change in outputs, or y-values divided by the change in inputs, or x-values. In essence the slope asks "For a given change in x, how much does y change?" or even more simply: "How steep is the graph of this function?". This can be represented mathematically by the formula:
Since we have a table of x,y pairs it's the last form of that equation that will be the most useful to us. To compute the slope we can use any two pairs, say the first two, and plug them into our formula:
We can check this answer by using a different pair, say the last two:
.
As a common sense check: Our y-values get smaller as our x-values get bigger so a negative slope makes sense.
m=-3
Since we have a table of x,y pairs it's the last form of that equation that will be the most useful to us. To compute the slope we can use any two pairs, say the first two, and plug them into our formula:
We can check this answer by using a different pair, say the last two:
As a common sense check: Our y-values get smaller as our x-values get bigger so a negative slope makes sense.
m=-3