SOLUTION: For what values of K does the equation have equal solutions? 2x^2-Kx+8=0

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Question 570721: For what values of K does the equation have equal solutions? 2x^2-Kx+8=0
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
When the equation has the form +f%28x%29+=+ax%5E2+%2B+bx+%2B+c+,
The quadratic formula to find the roots is
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
For real solutions, +b%5E2+-+4a%2Ac+ must be +0+ or positive
given:
+2x%5E2+-+K%2Ax+%2B+8+=+0+
+b%5E2+-+4a%2Ac+=+%28-K%29%5E2+-+4%2A2%2A8+
+b%5E2+-+4a%2Ac+=+K%5E2+-+64+
To be positive or zero,
+K%5E2+-+64+%3E=+0+
+K%5E2+%3E=+64+
+K+%3E=+8+
and, also, using (-) root
+K+%3C=+-8+
so,
+8+%3C=+K+%3C=+-8+