Answer:
hard question
Step-by-step explanation:
Surface area= 2(6x15)+2(7x15)+2(6x7)
=180+210+84
=474m
Volume=15x6x7
=630m^2
800 + 16x = 720 + 21x. Cancel out the 720 to get 80 + 16x = 21x. Subtract 16x from both sides to get 80 = 5x. Divide by 5 to get 16 = x, or x = 16. 16 hours. The charge is 800 + 16(16), = 720 + 21(16) which = 800 + 256 = 720 + 336 which = 1,056 = 1,056. Hope this helped!
Answer:
26: x=34
28: x=17
30: m=30
Step-by-step explanation:
<u>26:</u> 2x+22=90
subtract 22
2x=68
divide by 2
x=34
<u>28:</u> 18+3x+21=90
add 18 and 21
3x+39=90
subtract 39
3x=51
divide by 3
x=17
<u>30:</u> 43+87+m+20=180
add 43 and 87 and 20
m+150=180
subtract 150
m=30