The answer you have is correct
Answer:
Step-by-step explanation:
<u>Mean of four numbers a, b, c, and d is 8:</u>
- (a + b + c + d)/4 = 8
- ⇒ a + b + c + d = 32
<u>Mean of seven numbers x, y, z, a, b, c and d is 12:</u>
- (x + y + z + a + b + c + d)/7 = 12
<u>Substitute the sum of 4 numbers:</u>
- x + y + z + 32 = 7*12
- x + y + z = 84 - 32
- x + y + z = 52
<u>Mean of x, y and z is:</u>
Both A and C would be solutions to the equation.
In order to solve for this you must first get the equation equal to 0.
2x^2+5x+8=6 ----> subtract 6 from both sides
2x^2 + 5x + 2 = 0
Now knowing this we can use the coefficients of each one in descending order of power as a, b and c.
a = 2 (because it is the coefficient to x^2)
b = 5 (because it is the coefficient to x)
c = 2 (because it is the end number)
Now we can plug these values into the quadratic equation.





or -1/2 for the first answer

or -2 for the second answer
Answer:
20
Step-by-step explanation: