Relationship between two equations

[tinaravat840]

Q; In each question below one or more equations is/are given. On the basis of these, you have to find out the relationship between ‘x’ and ‘y’?

1. x^2-4x-5=0
2. y^2-18x+81=0

Options:

1. if y<x
2. if y>x
3. y=x
4. if relation between x and y can’t be determined
5. none of above.

Q : In each question below one or more equation(s) is/are given. On the basis of these,you have to find out the relationship between ‘x’ and ‘y’

1. x + y = 18
2. x^2 + y^2 +xy=279

Options:

1. if y<x
2. if y>x
3. y=x
4. if relation between x and y can’t be determined
5. none of above.

I should compare using the constant of the equation or by using discriminant and finding root of equation What approach should be followed ?

 

[Ishuda]

Q; In each question below one or more equations is/are given. On the basis of these, you have to find out the relationship between ‘x’ and ‘y’?

1. x^2-4x-5=0
2. y^2-18x+81=0

Options:

1. if y<x
2. if y>x
3. y=x
4. if relation between x and y can’t be determined
5. none of above.

Q : In each question below one or more equation(s) is/are given. On the basis of these,you have to find out the relationship between ‘x’ and ‘y’

1. x + y = 18
2. x^2 + y^2 +xy=279

Options:

1. if y<x
2. if y>x
3. y=x
4. if relation between x and y can’t be determined
5. none of above.

I should compare using the constant of the equation or by using discriminant and finding root of equation What approach should be followed ?

I'm not really sure what they are asking for but, for the first, I would use the quadratic equation 1. to find x, i.e.
x = ...
and then, since it asks for x and y in terms of one another, I would rewrite 2. as
y = [ 18 x - 81]^1/2

For the second, you can get
y = 18 - x
x = (18² - 279) / y
by squaring 1. and substituting. So use that to get a quadratic in x and do the same kind of thing as in the first one.

Just to be on the safe side, I would probably also provide the numerical answer for y.