What does x equals Y equals 7 plus 2x- 2x squared?

Answer 1

Y = 7 + 2X - 2X^2

set = to 0

7 + 2X - 2X^2 = 0

arrange in standard quadratic form

2X^2 - 2X - 7 = 0

I am too lazy to factor, so the quadratic equation........

-b +/- sqrt(b^2-4ac)/2a

a = 2

b = -2

c = -7

check with discriminant. b^2 - 4ac

-2^2 - 4(2)(-7) = 60; greater than 1; 2 real roots

-(-2) +/- sqrt[(-2)^2 - 4(2)(-7)]/2(2a)

2 +/- sqrt(60)/4

2 +/- 2sqrt(15)/4

not pretty, just, save factoring, exact