That's D. n² ÷ 5 because it says the division of n squared and 5.
<h3>
Answer: </h3><h3>
speed of train A = 44 mph</h3>
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Work Shown:
x = speed of train A
y = speed of train B
"train A travels 4/5 the speed of train B" (I'm assuming "train one" is supposed to read "train B"). So this means x = (4/5)y
distance = rate*time
d = x*7
d = (4/5)y*7 = (28/5)y represents the distance train A travels
d = y*7 = 7y represents the distance train B travels
summing those distances will give us 693
(28/5)y + 7y = 693
5*( (28/5)y + 7y ) = 5*693
28y + 35y = 3465
63y = 3465
y = 3465/63
y = 55
Train B's speed is 55 mph
4/5 of that is (4/5)y = (4/5)*55 = 4*11 = 44 mph
Train A's speed is 44 mph
Let's call your speed "a"
her walking speed is then "2a"
and her friend's scooter speed is 10 a
let's also call the distance you need to walk "d"
so the time (t)you need is:
d/t=a
t=d/a
and her time is:
t=

(half a distance with the speed of 2a and half a distance (d/2) with the distance of 10 a
now we count (we know that her time is 30 minutes)
30=

//multiply by 20a
600a=

600a=6d/divide by 6
100a=d
Now, in order to calculate your time we need to calculate:
t=d/a
but we know how much is d now!
t=

=100
which means that you need 100 minutes, or 1 h 40 minutes!!!
Answer:
x=2
x=-5
Step-by-step explanation:
You need to get everything on one side to have a quadratic equation:
x^2+6x-4 -(3x+6) = x^2+3x-10
All factors of 10 are 1*10 and 2*5.
5-2 = 3 and 5*-2 = -10
Factoring x^2+3x-10 gives us (x-2)(x+5)
x=2
x=-5