Answer:
Step-by-step explanation:
In order to resolve correctly this combined calculation, we need to resolve it in order:
First, the operation in parenthesis. Secondly, the powers. Then multiplications and divisions, and after all, substraction and adittion.
So, we first resolve the parenthesis: 
We multiply 12 by 2, and 3 by 1. The result is 
Then we resolve the powers:
Thirdly, we resolve the multiplications:
= 72
And finally, the addition:
16 + 72 - 7 = 81
Answer: (a) car exhaust; (b) chemicals and (d) people
Step-by-step explanation:
Indeed, it all starts from people. They are the ones who use the cars and make the pollution happen. It is also people who use chemicals to pan and find gold, for example, polluting rivers.
18 + 45m
...............................
To solve this you can make a proportion where the matching sides will correspond to each other. It should look something like this:
Now you must cross multiply
10*42 = 15*x
420= 15x
To isolate x divide 15 to both sides
420/15 = 15x/15
28 = x
Hope this helped!
~Just a girl in love with Shawn Mendes
Answer:
Circumference is π × diameter
