Question

Solve: 5x + 3y = 35; 2x + 4y = 28 *

a) x = 5, y = 4
b) x = -5, y = -4
c) x = 4, y = 5
d) x = 4, y = -5​

Answer 1

$\huge{\bold{\underline{\underline{Question:-}}}}$

Solve: 5x + 3y = 35; 2x + 4y = 28 *

a) x = 5, y = 4

b) x = -5, y = -4

c) x = 4, y = 5

d) x = 4, y = -5

$\huge{\bold{\underline{\underline{Solution:-}}}}$

In First equation :-

$= > 5x + 3y = 35$

$= > 5x = 35 - 3y$

$= > x = \frac{35 - 3y}{5}$

Now,

Substituting the value of 'x' in second equation :-

$= > 2x + 4y = 28$

$= > 2( \frac{35 - 3y}{5} ) + 4y = 28$

$= > \frac{70 - 6y}{5} - 4y = 28$

$= > 70 - 6y + 4y = 28 \times 5$

$= > 70 - 2y = 140$

$= > 2y = 140 - 70$

$= > 2y = 70$

$= > y = \frac{70}{2}$

$= > \large{\blue{\boxed{\orange{y = 35}}}}$

Now, putting the value of 'y' in first equation :-

$= > 5x + 3y = 35$

$= > 5x + 3 \times (35) = 35$

$= > 5x + 105 = 35$

$= > 5x = 35 - 105$

$= > 5x = ( - 70)$

$= > x = \frac{( - 70)}{5}$

$= >\large{\purple{\boxed{\pink{x = ( - 14)}}}}$

So, values of 'x'and 'y' are (-14) and 35 respectively.