Solve the equation x^2 + 4x - 7
By completing the square
give answer correct to two decimal places.
( p. s the answer is not -5.32 or 1.32 )

x = 1.32, -5.32

Step-by-step explanation:

x^2 + 4x - 7

Set equal to zero

x^2 + 4x - 7 =0

Add 7 to each side

x^2 + 4x =7

Take the coefficient of x and divide by 2

4/2

Square it

2^2 =4

Add to each side

x^2+4x+4 = 7+4

(x+2)^2 = 11

Take the square root of each side

x+2 = ±sqrt(11)

Subtract 2 from each side

x = -2 ±sqrt(11)

x=1.31662

x=-5.31662

To 2 decimal places

x = 1.32, -5.32

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)

step by step solution :

step   1   :

1.1     4 = 22

(4)3 = (22)3 = 26

equation at the end of step   1   :

  ((23) • 26)2

step   2   :

equation at the end of step   2   :

  (23 • 26)2

step   3   :

final result :

  218

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