Question

if x:y =3:4,then (7x+3y):(7x-3y)=?

Answer 1

if x:y = 3:4
so,
x=3
y=4

then ,

(7x+3y):(7x-3y)
(7*3 + 3*4) : (7*3- 3*4)
(21 + 12) : (21 - 12)
33 : 9
.i,e, 11:3

Answer 2

Answer:

Required answer is 11:3.

Step-by-step explanation:

Given,

$x \ratio \: y = 3 \ratio \: 4$

This is a problem of ratio.

Now question is what is ratio?

Ratio is a form of fraction.

If a and b are two numbers then ratio of a and b is $a \ratio \: b$

For example,

Ratio of 20 and 30

$= 20 \ratio \: 30 \\ = \frac{20}{30} \\ = \frac{2}{3} \\ = 2 \ratio \: 3$

Here we want to find value of (7x+3y):(7x-3y).

(7x+3y):(7x-3y)

$= \frac{7x + 3y}{7x - 3y}$

We are dividing denominator and numerator by y and get,

$\frac{ \frac{7x + 3y}{y} }{ \frac{7x - 3y}{y} } \\ = \frac{ \frac{7x}{y} + \frac{3y}{y} }{ \frac{7x}{y} - \frac{3y}{y} } \\ = \frac{7 \times \frac{x}{y} + 3 }{7 \times \frac{x}{y} - 3} \\ = \frac{7 \times \frac{3}{4} + 3}{7 \times \frac{3}{4} - 3} \\ = \frac{ \frac{21 + 12}{4} }{ \frac{21 - 12}{4} } \\ = \frac{ \frac{33}{4} }{ \frac{9}{4} } \\ = \frac{33}{4} \times \frac{4}{9} \\ = \frac{11}{3}$

So,(7x+3y):(7x-3y) = 11:3

Know more about ratio,

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