Answer:
1.) (11, -7/3), 2.) No solution. 3.) (1, 3)
Step-by-step explanation:
1.)
2x + 3y = 15
x - 3y = 18
Solve...use elimination method
2x + x + 3y - 3y = 15 + 18
3x = 33
x =11
11 - 3y = 18
-3y = 7
y = -7/3
(11, -7/3)
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2.) y = 4x + 4
y = 4x - 4
Use substitution.
4x + 4 = 4x - 4
4 = -4 FALSE NO Solution
3.) y = 5- 2x
4x + 3y = 13
Can use elimination method
2y = 10 - 4x
add it to 4x + 3y = 13
10 + 3y = 2y + 13
y = 3
3 = 5 - 2x
x = 1
(1, 3)
Turn the decimal into a whole number and then devide it
The speed of boat is 11 km/h in still water and speed of current is 7 km/h.
Step-by-step explanation:
Combined speed of boat and current while going down = 18 km/h
Combined speed while coming up = 4 km/h
Let,
Speed of boat = x
Speed of current = y
As boat and current were in same direction while going down,
x+y = 18 Eqn 1
We will subtract the speed of current while coming up because both the boat and current will be in opposite directions.
x-y = 4 Eqn 2
Adding Eqn 1 and Eqn 2
![(x+y)+(x-y)=18+4\\x+y+x-y=22\\2x=22](https://tex.z-dn.net/?f=%28x%2By%29%2B%28x-y%29%3D18%2B4%5C%5Cx%2By%2Bx-y%3D22%5C%5C2x%3D22)
Dividing both sides by 2
![\frac{2x}{2}=\frac{22}{2}\\x=11](https://tex.z-dn.net/?f=%5Cfrac%7B2x%7D%7B2%7D%3D%5Cfrac%7B22%7D%7B2%7D%5C%5Cx%3D11)
Putting x=11 in Eqn 1
![11+y=18\\y=18-11\\y=7](https://tex.z-dn.net/?f=11%2By%3D18%5C%5Cy%3D18-11%5C%5Cy%3D7)
The speed of boat is 11 km/h in still water and speed of current is 7 km/h.
Keywords: linear equation, speed
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Try this solution:
according to the graph it is possible to make up the solution of this system of equations: