2/4 = 1/2
1/2 - 2/7 LCD of 2 and 7 is 14
7/14 - 4/14 = 3/14
thats the answer
Let's say David's age right now is x years
x + 6 = 2(x - 7)
x + 6 = 2x - 14
x = 20
Therefor David is 20 years old
Step-by-step explanation:
The main thing to note here is that once you go past the decimal point, the answers also go past the decimal point.

First one has parentheses, second one doesn't.<span />
43 times 68.
43
x68
8 times 3 is 24. Bring the 2 over the 4.
8 times 4 is 32. Add 4. Equals 36.
Answer so far is 364.
Add a 0 before answering.
3 times 6 is 18. Bring the 1 over the 4.
4 times 6 is 24. Add 4. Equals 28.
Answer so far is 288
Add 364 + 288
Final answer is 652.