Question

9. If xy = k, k being a constant, then x and y vary in _____ .​

Answer 1

Answer:

9. If xy = k, k being a constant, then x and y vary in inversely.

Step-by-step explanation:

Inverse Proportion

Inverse proportion is the relationship between two variables when their product is equal to a constant value. When the value of one variable increases, the other decreases, so their product is unchanged. y is inversely proportional to x when the equation takes the form: y = k/x.

Answer 2

Answer:

If xy = k, k being a constant, then x and y vary in inversely.

Step-by-step explanation:

Given,

$xy = k \\ x = \frac{k}{y} \: and \: y = \frac{k}{x}$

It is clear that x and y vary in inversely.

This is a concept of Algebra.

Some important Algebra's formulas:

${(x + y)}^{2} = {x}^{2} + 2xy + {y}^{2} \\ {(x - y)}^{2} = {x}^{2} - 2xy + {y}^{2} \\ {(x + y)}^{3} = {x}^{3} + 3 {x}^{2} y + 3x {y}^{2} + {y}^{3} \\ {(x - y)}^{3} = {x}^{3} - 3 {x}^{2} y + 3x {y}^{2} - {y}^{3} \\ {x}^{3} + {y}^{3} = {(x + y)}^{3} - 3xy(x + y) \\ {x}^{3} - {y}^{3} = {(x - y)}^{3} + 3xy(x - y) \\ {x}^{2} - {y}^{2} = (x + y)(x - y) \\ {x}^{2} + {y}^{2} = {(x - y)}^{2} + 2xy \\ {x}^{2} - {y}^{2} = {(x + y)}^{2} - 2xy \\ {x}^{3} - {y}^{3} = (x - y)( {x}^{2} + xy + {y}^{2} ) \\ {x}^{3} + {y}^{3} = (x + y)( {x}^{2} - xy + {y}^{2} )$

Two more important Algebra's problem:

1) https://brainly.in/question/13024124

2) https://brainly.in/question/1169549

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