Question

if 3x+4y=10 and 4x+3y=4 then find the value of(x+y)​

Answer 1

Question :-

if 3x+4y=10 and 4x+3y=4 then find the value of(x+y).

Solution :-

Given equation :

• 3x + 4y = 10
• 4x + 3y = 4

Add both equation

$\sf:\longmapsto{3x + 4y + 4x + 3y = 10 + 4} \\ \\ \sf:\longmapsto{7x + 7y = 14} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Divide the equation by 7

$\sf:\longmapsto{x + y = 2} - - - - - (1)$

Subtract both equation

$\sf:\longmapsto{3x + 4y - (4x + 3y) = 10 - 4}$

when bracket opens sign will be changed

$\sf:\longmapsto{3x - 4x + 4y - 3y = 6} \: \: \\ \\ \sf:\longmapsto{ - x + y = 6 - - - - (2)}$

Add equation (1) and (2)

$\sf:\longmapsto{x + y + ( - x) + y = 2 + 6} \\ \\ \sf:\longmapsto{2y = 8} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \sf:\longmapsto{y = \frac{8}{2} } \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \bf:\longmapsto \red{y = 4} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Substituting y = 4 in equation (1)

$\sf:\longmapsto{x + 4 = 6} \\ \\\sf:\longmapsto{x = 6 - 4} \\ \\\bf:\longmapsto \red{x = 2} \: \: \: \: \:$

Hence,

• x = 2
• y = 4

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Learn more from brainly :

find the value of x-y

3x + 4y = 11------(1)

4x + 3y = 10-----(2)

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