Which expression has a positive value? (-5)(-9) 2-4 12-1-4) -3+(-7)
2 answers:
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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.