Question

Solve the quadratic equation 3x²–5x - 7 = 0

Give your answers to 3 significant figures.
Optional working
0.447
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Answer 1

To solve the quadratic equation 3x² – 5x - 7 = 0 we can use the quadratic formula which is x = [-b ± sqrt(b² - 4ac)] / 2a.

Here, a = 3, b = -5, and c = -7.

So, x = [5 ± sqrt((-5)² - 4*3*(-7))] / 2*3
x = [5 ± sqrt(25 + 84)] / 6
x = [5 ± sqrt(109)] / 6

So, the solutions to three decimal places are:

x = (5 + sqrt(109)) / 6 ≈ 1.897
x = (5 - sqrt(109)) / 6 ≈ -1.230

Please note that the given solution 0.447 doesn't solve this equation.