Answer:
the b value is -8, i just had this problem in my hw, and the value is -8 because the value of c will be equal to -b x a; it seems the other guy forgot the negative.
Step-by-step explanation:
We want to determine one coefficient in a quadratic equation given that we know one of the roots of the quadratic equation.
The value of b is -8.
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We know that for a quadratic equation:
a*x^2 + b*x + c
The roots are the values of x such that:
a*x^2 + b*x + c = 0.
Here we have the equation:
2*x^2 + b*x - 10 = 0
And we know that 5 is a root of this equation, then we can write:
2*5^2 + b*5 - 10 = 0
Now we can solve this for b:
2*25 + b*5 - 10 = 0
50 + b*5 - 10 = 0
b*5 = -50 + 10 = -40
b = -40/5 = -8
b = -8
Then the quadratic equation is:
2*x^2 - 8*x - 10 = 0.
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https://brainly.com/question/17177510
