Question

Solve the quadratic equation 3x^2 – 5x – 7 = 0 Give your answers to 3 significant figures.

Answer 1

Answer:

x≈2.57 or x≈-0.907

Step-by-step explanation:

plug the values a=3, b=-5 and c=-7 into

$x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}$

to find your answer

Answer 2

Answer:

2.57 or -0.907

Step-by-step explanation:

→ First state the quadratic formula

$\frac{-b+-\sqrt{b^{2}-4ac } }{2a}$

→ Identify the 'a', 'b' and 'c' variables

$ax^{2} +bx+c$

$3x^{2} -5x-7$

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

→ Substitute in the values into the quadratic formula

$\frac{5+\sqrt{5^{2}-4*3*-7 } }{2*3}=\frac{5+\sqrt{25+84 } }{6}=\frac{5+\sqrt{109 } }{6}=2.573384418$

→ Do the same for negative

$\frac{5-\sqrt{5^{2}-4*3*-7 } }{2*3}=\frac{5-\sqrt{25+84 } }{6}=\frac{5-\sqrt{109 } }{6}=-0.9067177515$