Please Help: In a class there are 11 boys and 19 girls.
The mean weight of all 30 children is 32.85 kg.
The mean weight of the 11 boys is 31.9 kg.
Work out the mean weight of the 19 girls.​

if you explain the the question more correctly i might be able to answer this better

step-by-step explanation:

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

if you was gonna solve for a, a is a   < -12

x= cost per bracelet

number of bracelets * x + shipping charge = total cost

so

9x+9=72