How the quadratic formula works:
For any quadratic equation ax² + bx + c = 0, the solution is
.
In the case of our equation 7x² - x = 7, first we need to subtract 7 from each side so that we have 0 on the right.
7x² - x - 7 = 0
Identify the values of a, b, and c.
a = 7, b = -1, and c = -7.
Plug these into our quadratic formula and solve.
There are two values for x: (1+√197)/14 and (1-√197)/14.
The approximate values for these are 1.073976 and -0.931119.
The sum of their speeds is 380 miles per hour. The difference of their speeds is 30 miles per hour. Then the faster plane is traveling at
.. (380 +30)/2 = 205 miles per hour
The slower plane's speed is 30 miles per hour less, so it is traveling at
.. 205 mph -30 mph = 175 miles per hour
Your number is 57.
Because....
47 + 10 = 57
67 - 10 = 57
Hope that helps!
Answer:
The missing number (i.e. the coefficient of x) is 5.
Step-by-step explanation:
5x - 8 - 9x = -4x + 8
-4x - 8 = -4x + 8
-8 ≠ 8