How do you solve 27 x + 4 = 40 x ^2 using the quadratic formula?

1 Answer
Nghi N
May 12, 2017

4/5 and (-1/8)

Explanation:

Solve the quadratic equation:
y = 40x^2 - 27x - 4 = 0
Use the improved quadratic formula (Socratic Search)
D = d^2 = b^2 - 4ac = 729 + 640 = 1369 --> d = +- 37
There are 2 real roots:
x = -b/(2a) +- d/(2a) = 27/80 +- 37/80 = (27 +- 37)/80
x1 = 64/80 = 4/5
x2 = - 10/80 = - 1/8

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