Question

2.For what value of k will the equation 3x+4y+2=0 and 9x+12y+k=0 represent coincident line
​

Answer 1

Answer:

(1) x2 + 4x – 5 = 0 , x = 1, –1

For x=1(1)2+4(1)-5=0⇒1+4-5=0⇒5-5=0

So, x = 1 is a solution of the given equation.

For x = –1

(-1)2+4(-1)-5=0⇒1-4-5=0⇒-3-5=0⇒-8≠0

So, x = –1 is not a solution of the given equation.

Thus, only x = 1 is root of the given equation.

(2) 2m2 – 5m = 0, m=2,

5

2

When m=22(2)2-5(2)=0⇒8-10=0⇒-2≠0

So, m = 2 is not a solution of the given equation.

When m=

5

2

2(

5

2

)2-5(

5

2

)=0⇒

25

2

-

25

2

=0

So, m=

5

2

is a solution of the given quadratic equation.

Thus, only m=

5

2

is a root of the given quadratic equation