Answer:
Step-by-step explanation:
How to write numbers in standard form:
Write the first number 8.
Add a decimal point after it: 8.
Now count the number of digits after 8. There are 13 digits.
So, in standard form: 81 900 000 000 000 is 8.19 × 10¹³
10(x/2 + 8) = 11, expand
10x/2 + 80 = 11
5x/2 = 11-80= -69
5x = -138
x = - 138/5