Answer:
8
Step-by-step explanation:
0 = –x^2 + 4x – 2
This is of the form
ax^2 +bx +c
a = -1 b = 4 x = -2
The discriminant is
b^2 -4ac
4^2 - 4(-1)(-2)
16 - 8
8
Find 20% first
20% of 84 is 16.8
tax is 7% of 84 which is 5.88
total
84+16.8+5.88=$106.68
You should look to units of measure when setting up problems. when math is done correctly, the units cancel out just as numbers and variables do.
(miles / hr) * hr = miles
Speed = (miles / hr)
So if the Train W is traveling at x miles/hr
Then Train E is traveling (x+14) miles/hr
The combined distance they two trains travel is 320 miles
2x + 2(x+14) = 320
2x + 2x + 28 = 320
4x + 28 = 320
4x = 292
x = 292/4
x = 73 miles/hr
remember we set x as the speed for Train W
so Train E is going 73 + 14 = 87 miles/hr
Remove decimal for 4 move other decimal over once to the right and divide like normal