F(13) means x equals 13.
Replace x in the equation with 13 and solve:
-13 + 3 = -10
F(13) = -10
What is 100% of the mass ?
both (0,350) and (250,700) fall in the shaded are
and check:
350 *3 = 1050, which is more than 1000 and more than double the amount of hotdogs ( 0)
700 *3 = 2100, so over 1000 and more than double the amount of hotdogs(250*2=500)
so those 2 are correct
an equivalent expression is 5y+4
there is 3y which is y+y+y
so you have y+y+y+y+4+y
there are 5 y so it is 5y
then you have +4
5y+4