How do I write this as x=... etc.? How do I isolate x so that I can solve x for any given y?
-
y = 40x^3+60x^2+30x+5
= 5(8x^3 + 1) + 30x(2x + 1)
= 5(2x + 1)(4x^2 - 2x + 1) + 30x(2x + 1)
= (2x + 1)[5(4x^2 + 4x + 1)]
= (2x + 1)[5(2x + 1)^2]
y = 5(2x + 1)^3
x = -1/2 => root
= 5(8x^3 + 1) + 30x(2x + 1)
= 5(2x + 1)(4x^2 - 2x + 1) + 30x(2x + 1)
= (2x + 1)[5(4x^2 + 4x + 1)]
= (2x + 1)[5(2x + 1)^2]
y = 5(2x + 1)^3
x = -1/2 => root