I need help on number 2,3

Use the x-intercept method to find all real solutions of the equation. x^3-10x^2+27x-18=0

If f(x) = x+8 and g(x) = 4x- 3, find (f+g)(x)

Heather is writing a quadratic function that represents a parabola that touches but does not cross the x-axis at x = -6. which function could heather be writing? fx) = x2 + 36x + 12 = x2 - 36x - 12 f(x) = -x + 12x + 36 f(x) = -x? - 12x - 36