Answer:
3.9 mi/h
Step-by-step explanation:
If the boy is rowing perpendicular to the current, the two vectors form a right triangle.
AB represents the downstream current, BC is the speed across the river, and AC is the ground speed of the boat
AC^2 = 2.4^2 + 3.1^2 =5.76 + 9.61 = 15.37
AC = sqrt(15.37) = 3.9 mi/h
The boat's speed over the ground is 3.9 mi/h.
You can use the trigonometric identity

.

The requirement that

eliminates -1/6 from being another solution.
$30 because you are taking away 20% of $30 and then adding back that 20%.
Answer:
x-intercept: 
y-intercept: 
Step-by-step explanation:
To find the x-intercept, substitute in
for
and solve for
.


Simplify 2(0): 
Subtract 0 - 3 = -3: 
Subtract 7 from both sides: 
Simplify: 
Divide both sides by -4 

To find the y-intercept, substitute in
for
and solve for
.


Switch sides: 
Simplify -4(0): 
Add 3 to both sides: 
Simplify: 
Divide both sides by 2: 
