Answer:
#3: x is approximately 0.37, -5.37, #4: x is approximately 4.19, -1.19
Step-by-step explanation:
You can solve using the quadratic equation or by solving with the perfect square
= 
x is approximately 0.37, -5.37
Going upstream: 432 km / 6 hours = 72 km/h
Going downstream: 384 km / 4 hours = 96 km/h
Going upstream against the current means that the effective speed is:
r_boat - r_current = 72
Meanwhile, going downstream with the current means;
r_boat + r_current = 96
Adding both equations (to cancel out r_current) gives:
2r_boat = 72 + 96
r_boat = 84 km/h
Substituting back into one of the original equations: r_current = 12 km/h.
21 • (3k + 2m)
Step by step solution :
Step 1 :
Step 2 :
Pulling out like terms :
2.1 Pull out like factors :
9k + 6m = 3 • (3k + 2m)
Final result :
21 • (3k + 2m)
Answer:
Option 2
Step-by-step explanation:
Minimum value is going to be in the y part of our coordinate, so we can just look there. I went ahead and used a graphing calculator to make things easy.
Starting off with option 2, we can see the minimum is -10. And in option 4 we can see the smallest y value is -6.
Using a graphing calculator (I used desmos), we can graph these other functions and figure out their minimums.
Option 1's y minimum is -7, and Option 3's y minimum is -2.25.
Option 1: -7
Option 2: -10
Option 3: -2.25
Option 4: -6
The questions asks for the <em>smallest</em> minimum value, which in this case is option 2.
#2
2x - 4y = -2
2x + 3y = -16
------------------subtract
-7y = 14
y = 14/-7
y = -2
2x - 4y = -2
2x - 4(-2) = -2
2x + 8 = -2
2x = -2 -8
2x = -10
x = -10/2
x = -5
answer x = -2 and y = -5
check:
2(-5)- 4(-2) = -2
-10 +8 = -2
-2 = -2.....true
2x + 3y = -16
2(-5)+3(-2) = -16
-10 + (-6) = -16
-16 = -16...true
