The speed of boat in still water is 15km/hr if needs 4 more his to travel 63 km against the current of a river than it needs to travel down the river determine the system of equation

Step-by-step explanation:

The systems of equations are

Let us assume the rate of the current be c

Now actual speed against the current is (15 - c)

And, the actual speed with the current is (15 + c)

Here we applied the time formula i.e. distance by speed

Also the upstream time  - downstream time = 4

Now the equations are

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b