Dup= 72 miles
<span>ddown= 120 miles </span>
<span>v= riverspeed </span>
<span>rup= 32mph - v </span>
<span>rdown= 32mph + v </span>
<span>t both ways= t </span>
<span>d=r*t </span>
<span>d/r=t </span>
<span>t=ddown/rdown </span>
<span>t=dup/rup </span>
<span>dup/rup = ddown/rdown </span>
<span>(72)/(32-v)=(120)/(32+v) </span>
<span>3840-120v=2304+72v </span>
<span>1536=192v </span>
<span>v=8</span>
The area is just the dimensions multiplied, so multiply 7 by 18 and you get 126.
After solving the equation (work shown in image) your answer would be x > -2. I drew an image of how the number line should look at least similar to, using the solution.
*whenever you divide or multiply with a negative number reverse/flip the sign
< or > signs will always have an open circle
≥ or ≤ signs will have a closed/filled in circle
TIP: To know which way the arrow should point, look at the sign and think of it as an arrow.
< would have the arrow on the number point
this way: <-
or > which would have the arrow on the number line point this way: ->
Taking 30% percent of something is the same as multiplying by .3
so, .3*20 = 6