Determine the type and number of solutions of −4x2 − 3x + 7 = 0.
1 answer:
Answer:
Step-by-step explanation:
You have to use the discriminant for this. If the quadratic is , then
a = -4, b = -3, and c = 7. The formula for finding the discriminant is
which comes from the quadratic formula, but without the square root sign. Filling in:
which simplifies down to
D = 9 + 112 so
D = 121. This is a perfect square, so the solutions will be 2 real. Just so you know, you will NEVER have a solution like the one offered in the third choice down. If you have one imaginary root, you will ALWAYS have a second by the conjugate rule.
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We know for our problem that the zeroes of our quadratic equation are 
and 
, which means that the solutions for our equation are 
and 
. We are going to use those solutions to express our quadratic equation in the form 
; to do that we will use the <span>zero factor property in reverse:
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Now, we can multiply the left sides of our equations:
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=
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Now that we have our quadratic in the form