If f(1)=7 and f(n)=-2f(n-1) then find the value of f(4) please explain it im confused

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

Which point has an coordinates of (2,0) ? a

What is the probably of getting heads when poing a coin and getting a number greater than or equal to 5 when rolling a single diea) 1/6b) 1/3c) 1/4d) 1/12