Question

If 2x + y = 23 and 4x - y = 19, find the value of (3y - 2x)​

Answer 1

S O L U T I O N :

We have two equation;

• 2x + y = 23..............(1)
• 4x - y = 19................(2)

$\underline{\underline{\tt{Using\:\:by\:\:substitution\:\:method\::}}}$

From equation (1),we get;

$\mapsto\tt{2x + y = 23}$

$\mapsto\tt{ y = 23-2x............(3)}$

Putting the value of y in equation (2),we get;

$\mapsto\tt{4x - (23-2x ) = 19}$

$\mapsto\tt{4x - 23+2x = 19}$

$\mapsto\tt{6x -23 = 19}$

$\mapsto\tt{6x = 19+23}$

$\mapsto\tt{6x = 42}$

$\mapsto\tt{x = \cancel{42/6}}$

$\mapsto\bf{x = 7}$

∴Putting the value of x in equation (3),we get;

$\mapsto\tt{y = 23-2(7)}$

$\mapsto\tt{y = 23-14}$

$\mapsto\bf{y = 9}$

Now,

⇒ 3y - 2x

⇒ 3(9) - 2(7)

⇒ 27 - 14

⇒ 13

Thus,

The value of (3y - 2x) will be 13 .