Need help please , I know the basic math. how do I solve this?
2 answers:
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Hi there!
Let's solve this equation step by step!
First add 7 to both sides.
Next we need to take a look at the meaning of the stripes between our variable. Those stripes mean we are dealing with an absolute value function. The absolute value stripes make everything between the stripes positive; also when we plug in a number. In this particular question we can plug in both -13 and 13 at the position of n, because when -13 is made positive, it fulfils the equation.
Hence,
or 
~ Hope this helps you!
Let's solve this equation step by step!
First add 7 to both sides.
Next we need to take a look at the meaning of the stripes between our variable. Those stripes mean we are dealing with an absolute value function. The absolute value stripes make everything between the stripes positive; also when we plug in a number. In this particular question we can plug in both -13 and 13 at the position of n, because when -13 is made positive, it fulfils the equation.
Hence,
~ Hope this helps you!
Normal-travel DATA:
distance = 240 km
rate = x km/h
time = d/r
= 240/x hrs
_______________________
Bad weather DATA:
distance = 240 km
rate = (x-20) km/h
time = 240/(x-20) hrs
______________________
Bad time - normal time = 2 hrs
240/(x-20) - 240/x = 2
120/(x-20) - 120/x = 1
120x -120(x-20) = x(x-20)
20 = x^2 -20x
x^2 - 20x - 20 = 0
x = [20 +- sqrt(20^2 - 4*1*-20)]/2
x = [20 +- sqrt(480)]/2
x = [20 +- 4sqrt(30)]/2
x = 10 +- 2sqrt(30)