Question

Solve the following equations by substitution method.

$5x+3y=21;2x-y=4$

• A. $x=3,y=2$
• B. $x=-3,y=2$
• C. $x=3,y=-2$
• D. None of these

Answer 1

The correct option is A $x=3,y=2$

$5x+3y=21$.........(1)

$2x-y=4$...............(2)

$y=2x-4$

$5x+3(2x-4)=21$.........putting value of $y$ in (1)

$\Rightarrow 5x+6x-12=21$

$\Rightarrow 11x=33$.......................$x=3$

Putting value of $x$ in (2)

$6-y=4$..........................$y=2$