Question

Solve by using tables. Give each answer to at most two decimal places. –2x2 – 4 = –8x (1 point) 0.59, 3.41 –3.41, –0.59 1.17, 6.83 –1.41, 1.41

Answer 1

0.59, 3.41

Explanation

–2x2 – 4 = –8x is a quadrilatic equation

–2x2 – 4 = –8x ⇒ -2x² + 8x - 4 = 0

2x² - 8x + 4 = 0

x² - 4x + 2 = 0

Using the complete square method to solve;

x² - 4x = -2

x² - 4x + 2² = -2 + 2²

(x - 2)² = 2

x - 2 = √2

x = √2 + 2

∴ x = 1.414 + 2 or x = -1.414 + 2

x = 3.414 x = 0.5858

= 3.41 = 0.59

Answer 2

x=3.414 and x=0.59 is the desired answer.

Explanation:

We are given a quadratic equation as :
`-2x^2-4=-8x\\=> 2x^2-8x+4=0`

on dividing both side by 2 we have the equation as

`x^2-4x+2=0`

on solving for the roots of the equation using the quadratic formula we get that
`x=2\pm √(2)`

`x=2+√(2)` and
`x=2-√(2)`

x=2+1.414 and x=2-1.414

Hence , x=3.414 and x=0.586≈0.59.