Answer:
Step-by-step explanation:
A 2nd order polynomial such as this one will have 2 roots; a 3rd order polynomial 3 roots, and so on.
The quadratic formula is one of the faster ways (in this situation, at least) in which to find the roots. From 2x^2 + 4x + 7 we get a = 2, b = 4 and c = 7.
Then the discriminant is b^2 - 4ac, or, here, 4^2 - 4(2)(7), or -40. Because the discriminant is negative, we know that the roots will be complex and unequal.
Using the quadratic formula:
-4 ±√[-40] -4 ± 2i√10
x = ------------------ = ------------------
4 4
-2 ± i√10
Thus, the roots are x = ------------------
2
Answer:
D is the right one im 100% sure on it
Step-by-step explanation:
There are 5 solutions for this system.
x^2 + 4y^2 = 100 ____1
4y - x^2 = -20 ____2
Add both 1 & 2 together. x^2 gets cancelled
4y^2 + 4y = 80 (send 80 to the other side and divide by 4)
Then equation the becomes : y^2 + y -20 =0
Now factorise the equation: (y+5) (y-4) = 0
Solve for y : y = -5 and y = 4
Using the values of y to find the values of x. From equation 1:
x^2 = 100 - 4y^2 x = /100 - 4y^2 (/ means square root) Replace values of y
y = -5, x = /100 - 4(-5)^2 = /100 - 100 = 0
y = 4, x = /100 - 4(4)^2 = / 100 - 64 = /36 = -6 or 6
Thus we have 6 solutions y = -5, 4 and x = -6, 0, 6
The answer is A, not sure about the expression though. Sorry
