14. Solve: 3x² + 5x - 12 = 0

B. 4-3

C. 8, - 18

b

Step-by-step explanation:

The equation:

3

x

2

-

5

x

-

12

=

0

is in the form:

a

x

2

+

b

x

+

c

=

0

with

a

=

3

,

b

=

-

5

,

c

=

-

12

The roots are given by the quadratic formula:

x

=

-

b

±

√

b

2

-

4

a

c

2

a

x

=

5

±

√

(

-

5

)

2

-

4

(

3

)

(

-

12

)

2

(

3

)

x

=

5

±

√

25

+

144

6

x

=

5

±

√

169

6

x

=

5

±

13

6

That is:

x

=

5

+

13

6

=

18

6

=

3

or

x

=

5

-

13

6

=

-

8

6

=

-

4

3