Find the value of k for which the equation has equal roots x^2+(k+9)x+15=0

k=-9±2√15

Step-by-step explanation:

For the above quadratic to have equal roots then it's discriminant b²-4ac must equal 0

By comparing x²+(k+9)x+15=0 with ax²+bx+c=0,a=1,b=k+9 and c=15

(k+9)²-4(1×15)=0

k²+18k+81-60=0

k²+18k+21=0(factorize)

k=-9±2√15

it costs $20 to interview each person for a survey. find the cost to obtain a +- 3% margin of error.

step-by-step explanation:

copy and paste, put it in google

22 and 22

step-by-step explanation:

10 plus 12 equals 22.

12 plus 10 also equals 22 because regardless of what order they're in, they're gonna equal the same thing.