Answer:
-9y-2(2-7y)+4 expand the brackets using-2
Step-by-step explanation:
-9y-4+14y+4
arrange the like terms
-9y+14y-4+4
=5y becoz -4+4=0
ans=5y
Answer:
n = 61 costumers
Step-by-step explanation:
For calculating the number of costumers he should sample we use the next equation:

Where E is the error that we are prepared to accept, in this case E = 0.15
How we don't know the value of p, we can estimate it like p = 0.5
∝ = 1-0.98 = 0.02
1-∝/2 = 0.99


n = 60.32 costumers
n ≈ 61 costumers
Calculate the difference, Reduce the fraction with 2, Multiply the numbers
(-10)^2+(7/2)^2-10
To raise a fraction to a power, raise the numerator and denominator to that power
100+49/4 -10
Calculate the sum
409/4
Or
102 1/4
Or
102.25