An estimate helps you place the decimal point when multiplying because if you find out how many decimals there are and once you are done doing you estimated multiplication you put two decimal points after that.
Hope I helped some what and didn't make you confused.
Answer:
6r + 7 = 13 + 7r
subtract 6r from both sides...
7 = 13 + r
subtract 13 from both sides...
-6 = r
r = -6
Step-by-step explanation:
Four times d to the third minus ten
