Question

Solve the following systems of simultaneous linear equations by the method of elimination by equating the coefficient.
$0.4x+0.3y=1.7$
$0.7x-0.2y=0.8$

Answer 1

The given equations are
$0.4x+0.3y=1.7$ ..........(i)
$0.7x-0.2y=0.8$ .........(ii)
Multiplying equation (i) by $2$ and (ii) by $3$

$0.8+0.6=3.4$

$2.1-0.6=2.4$

and then adding, we get
$2.9x=5.8$
$\Rightarrow x=2$
Substituting the value of x in (i), we get
$0.4\times 2+0.3y=1.7$
$\Rightarrow 0.3y=1.7-0.8$
$\Rightarrow 0.3y=0.9$
$\Rightarrow y=3$