if Y = X2(xsquared) -6x - 8 find the value(s) of x when y =1.

Question

yes there was a typo its x squared i don't know how to rise the 2

Answer 1

x squared is usually typed like this: x^2 (means x raised to two) :)
anyways, the given in y = x^2 - 6x - 8 and we need to find x when y = 1. thus we substitute y into the equation:
y = x^2 - 6x - 8
1 = x^2 - 6x - 8
now to solve for x,, first we make one side of the equation equal to zero. in this case let's transpose 1 to the right side so that the left side would be zero. to transpose, we take the opposite sign of 1 from positive to negative:
0 = x^2 - 6x - 8 - 1
0 = x^2 - 6x - 9
since it's not factorable, we use the quadratic formula:
x = [-b +- sqrt(b^2 - 4*a*c)]/(2*a)
where
a = numerical coefficient of x^2
b = numerical coefficient of x
c = the constant
note: +- is plus or minus operation
in the equation x^2 - 6x - 9,
a = 1 , b = -6 and c = -9 . substituting:
x = [-(-6) +- sqrt((-6)^2 - 4*(1)*(-9))]/(2*(1))
x = [6 +- sqrt (36 + 36)]/2
x = (6 +- sqrt(72)]/2
x = [6 +- 6*sqrt(2)]/2
now let's split this to + and -
for plus:
x = [6 + 6*sqrt(2)]/2
x = 3 + 3*sqrt(2)
**this is the first root.
for minus:
x = [6 - 6*sqrt(2)]/2
x = 3 - 3*sqrt(2)
**this is the second root.

thus, at y=1, x = 3+3*sqrt(2) and x = 3-3*sqrt(2)

hope this helps~ :)

Answer 2

type x squared as x^2

1 = x^2 - 6x - 8
x^2 - 6x - 9 = 0
Use the quad formula to solve

(I got x = 3 +/-sqrt(2) )