NEED IN NEXT HOUR solve the following equation: 20= 4t -5t^2

2/5 ±i4/5sqrt(6)= t

Step-by-step explanation:

20= 4t -5t^2

Rewriting

20 = -5t^2 +4t

Divide by -5

20 = -5t^2 +4t

20/-5 = -5/-5t^2 +4/-5t

-4 = t^2 -4/5 t

Complete the square

Take the coefficient of t

-4/5

Divide by 2

-4/10 = -2/5

Square it

(-2/5)^2 = 4/25

Add to each side

-4 +4/25 = t^2 -4/5 t + 4/25

-100/25+4/25 = ( t-2/5)^2

-96/25 = ( t-2/5)^2

Take the square root of each side

sqrt(-96/25) = sqrt(( t-2/5)^2)

±isqrt(96/25)=( t-2/5)

±i4/5sqrt(6)=( t-2/5)

Add 2/5 to each side

2/5 ±i4/5sqrt(6)= t

15%

step-by-step explanation:

use the table and count the number of guesses that has two correct answers.

the following are two correct answers

10010, 01100, 11000

a total of 3 numbers having 2 correct guesses out of 20 questions.

probability of getting 2 correct guesses = the number of questions getting 2 correct answers / total number of questions.

= 3/20

to convert it into percent multiply by 100, we get

= 3/20 * 100

= 15%

the answer is 15%

you.

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.