Question

Find the coordinates of the x -intercepts for the equation of the graph below. y = x 2² + 3 x − 108

Answer 1

Answer:

Find

d

y

d

x

of

y

equation

y

=

3

x

2

−

x

3

d

y

d

x

=

6

x

−

3

x

2

Then from the point (1,2) we can obtain the x value which is 1

Insert

x

=

1

into

d

y

d

x

d

y

d

x

=

6

(

1

)

−

3

(

1

)

2

d

y

d

x

=

3

To form the equation we have to base it from the original equation

y

=

m

x

+

c

we know that m=3 from

d

y

d

x

=

3

y

=

3

x

+

c

use the coordinates given fro x and y values to find c

(1,2) x=1 , y=2

(

2

)

=

3

(

1

)

+

c

c

=

−

1

Then we put c back into the general form to get the final tangent equation

y

=

3

x

−

1