Question

How do you work the intercepts out in solving the following equation graphically
y=x3(cubed)-7x2(squared) - 14x +120

Answer 1

to find y intercept set x= 0
to find x intercept set y = 0 and solve for x

Answer 2

ok to find the intercepst you have to make y=0 and solve for x to find x intercepts and x=0 and solve for to find y intercepts.

Answer 3

can you do the example and show me workings please

Answer 4

x=0 gives y intercept => 120
y=0 gives x intercept
x^3 - 7x^2 -14x +120 =0
x^3 + 4x^2 - 11x^2 - 44x + 30x + 120=0
=> (x^3 - 11x^2 +30x) + (4x^2 -44x + 120)=0
can you do now?

Answer 5

or you may use rational root theorem..

Answer 6

Sorry shubhamsrg i dont get the second line. how did you end up with 4x^2 - 11x^2 etc

Answer 7

Integer factor of the coefficient of the first term and integer factor of the last term which is the constant*

Answer 8

rational root theorem
all possible roots of the equation =
±p/q

Answer 9

x^3 - 7x^2 - 14x + 120

ok to find y intercept set all values of x to 0

so y intercept = 0 - 0 - 0 + 120

now to find your x intercept set y = 0 and solve for x

Answer 10

Y is easy, need someone to show me how to do x. Need some workings

Answer 11

I know the answer is (-4,0) (5,0) and (6,0)

Answer 12

well what did you learn when you have a 3 degree polynomial to solve for x when y = 0 ?

There are a couple of ways you can do it

1) draw the graph and see where x is 0
2) Use the quadratic equation and plug in the values

The easiest is by using the quadratic formula