Question

The solution of the linear equations
x+y=4; 2x- 5y = 1 is:
A. x = 3; y=1
B. X = 3; y = -1
D r = -3; y = -1
C. X = 1; y=3​

Answer 1

$Given \:pair \:of \: linear \:equations :$

$x + y = 4 \implies y = 4 - x \: ---(1)$

$and \: 2x - 5y = 1 \: --(2)$

/* Substitute (1) in equation (2) ,we get */

$2x - 5(4-x) = 1$

$\implies 2x - 20 + 5x = 1$

$\implies - 20 + 7x = 1$

$\implies 7x = 1 + 20$

$\implies 7x = 21$

$\implies x = \frac{21}{7}$

$\implies x = 3$

/* Now, put x = 3 in equation (1) , we get */

$y = 4 - 3 = 1$

Therefore.,

$\red { (x,y) }\green {= (3,1)}$

$Option \:pink { (A) } \:is \: correct$

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