We have a + b = 180 and a = 12 + b;
Then, 12 + b + b = 180;
12 + 2b = 180;
2b = 168;
b = 84;
a = 12 + 84;
a = 96;
A negative plus a negative equals a negative so it's just -17
After having done this on paper:

We want to isolate the variable, and the first step is to subtract the 8.

Since the <em>n</em> is being multiplied by 3, and that = 8, we can multiply both sides by 3.
<em>n</em> = 24
Let me know if this helped you understand better.
Also, you can check this by substituting in 24 for <em>n</em>.
Answer:
Option b is the right answer.
Answer:
400,000
Step-by-step explanation:
The given sum is 164,215+216,088
We simplify this to get:
164,215+216,088=380,303
The digit at the hundred thousand position is the rightmost 3.
The digit after it is 8.
Since 8≥5 we round up.
We add 1 to 3 to get 4 and replace all digits to the right with zeros.
We round to the nearest hundred thousand to get:
400,000