Question

Solve the equation 3x^2-x-7=0and give your answer correct to two decimal places

Answer 1

Answer:1.7 and 1.36

Step-by-step explanation:

By formula

(1+√85) /6=1.7

(1-√85) /6=1.36

Answer 2

Answer:

Correct to two decimal places is 1.70  or -1.37.

Step-by-step explanation:

3x^2 – x – 7 = 0

comparing it with ax^2 + bx + c = 0

a = 3, b = - 1, c = - 7

x = (-b ± √ b^2 - 4ac ) / 2a

= - ( - 1 ) ± √  { ( - )^2 - 4 . 3 . (-7) }    /    { 2 ( 3) }

=  1  ± √  ( 1  + 84   /  6

=  1  ± √  85   /  6

=  1  ± 9.22   /  6

=  1  +  9.22   /  6   or             1  -  9.22   /  6

=  10.22   /  6   or             -8.22   /  6

=  1.70   or     -1.37

∴   Correct to two decimal places is 1.70  or -1.37