Quadratic formula Lesson 1

Question 1

The quadratic formula is …

Answer 1

x = -b +/- square root b2 - 4ac

2a

Question 2

Silver example :

Solve the following to 2 decimal places.

2x2 - 5x - 6 = 0

a = 2

b = -5

c = -6

Answer 2

First:

x = 5 +/- square root -5(squared) -4 x 2 -6
2 x 2

Second:

x = 5 +/- square root 25 + 48
4

Third:

x = 5 + sqaure root 73
4

x = -5 square root 73
4

Finally:

(If +5) x = 3.39 (2dp)
(If -5) x = -0.89 (2dp)