4k(3c-10)
factoring:
14ck *2 + 10ck *2 - 16ck - 40k
28ck -16ck - 40k
12ck - 40k
15 + .65x = 80
15 + .65x = 80
15 - 15 + .65x = 80 - 15
.65/.65x = 65/.65
x = 100
Beth swam 100 laps.
x > -1
-2x+5 < 7
-2x<2
Now since you divide by (-1) to get positive 2,you need to flip the sign
(-2)/(-1)= 2 2/(-1)=-2
SO
2x>-2
x > -1
To check the solution do not replace the x by -1 because it shouls be more than -1 (You can choose 0,1,2,3....)
Example choose x=3
-2x3+5<7
-6+5<7
-1<7
The answer you are looking for is 65.