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

solve systems of equations by graphing. a system of linear equations contains two or more equations e.g. y=0.5x+2 and y=x-2. the solution of such a system is the ordered pair that is a solution to both equations. to solve a system of linear equations graphically we graph both equations in the same coordinate system