F(x)=x^3+x^2-42x what are the zeros

F(x)=x^3+x^2-42x
Roots
 Solve for x over the real numbers
x³+x²-42x=0
Factor the left-hand side
   The left-hand side factors into a product with three terms
x(x-6)(x+7)=0
Find the roots of each term separately
 Split into three equations
x-6=0  x=0  x+7=0
Look at the first equation and solve for x
 Add 6 to both sides
x=6  x=0 x+7=0
Look at the third equation and solve for x
 Subtract 7 from both sides

x=6    x=0  x=-7

4should be the last one n=4

A) for the n row: 22+(n-1)×6therefore,b) 100-22=78that means (n-1)×6=7878÷6=1313+1=1414th row has 100 seats