Answer:
david was. 9 seconds faster than Justin.
Step-by-step explanation:
8.1-7.2= .9
0.9 seconds
Since Justin came in slower, you would put his time first:
8.1 - 7.2
Doing that gets you 0.9
Expand
4a - 4b + 6b
Collect like terms
4a + (-4b + 6b)
Simplify
<u>4a + 2b</u>
-3
x - 4 = - 7
Carry over the - 4 and make x the subject.
x= - 7 + 4
x= - 3
Therefore x is - 3
