Solve the equation 2x2+8x -1 = 0
by completing the square.
Give your answers correct to 2 decimal places.

x ≈ - 4.12 , x ≈ 0.12

Step-by-step explanation:

2x² + 8x - 1 = 0 ( add 1 to both sides )

2x² + 8x = 1 ( factor out 2 from the first two terms )

2(x² + 4x) = 1

To complete the square

add/ subtract ( half the coefficient of the x- term )² to x² + 4x

2(x² + 2(2)x + 4 - 4) = 1

2(x + 2)² - 8 = 1 ( add 8 to both sides )

2(x + 2)² = 9 ( divide both sides by 2 )

(x + 2)² = ( take square root of both sides )

x + 2 = ± = ± ( subtract 2 from both sides )

x = - 2 ±

Then

x = - 2 - ≈ - 4.12 ( to 2 dec. places )

x = - 2 + ≈ 0.12 ( to 2 dec. places )

sup

step-by-step explanation:

the final amount you will pay is $68.04.

the tip is determined by the pre-tax amount, so we calculate the tip based on the original bill, not after we've added sales tax.

to find the tip:

we can divide 54.00 by 100 to get 1% of 54. then we multiply that by 18.

54 / 100 = .54

.54 x 18 = 9.72

tip = 9.72$

to find the tax:

we can divide 54.00 by 100 to get 1% of 54. then we can multiply that by 8 to get 8%.

54 / 100 = .54

.54 x 8 = 4.32

tax= 4.32

now we can add the tip and tax to the bill to get our total.

54 + 9.72 + 4.32 = 68.04

total: $68.04

step-by-step explanation: