Question

Solve for x and y:

$0.4x+0.3y=1.7,0.7x-0.2y=\mathrm{0.8.}$

Answer 1

The given system of equation is

$0.4x+0.3y=1.7$

$0.7x-0.2y=0.8$

Multiplying both sides by 10

$4x+3y=17$……………………….. (i)

$7x-2y=8$ …………………………… (ii)

From (ii)

$7x-2y=8$

$x=\left(\frac{8+2y}{7}\right)$…………… (iii)

Substituting the value of x in equation (i) we get,

$\Rightarrow \left(\frac{4(8+2y)}{7}\right)+3y=17$

$\Rightarrow 32+29y=119$

$\Rightarrow 29y=87$

$\Rightarrow y=3$

Putting the value of y in the equation (iii)

$\Rightarrow x=\left(\frac{8+2\left(3\right)}{7}\right)$

$\Rightarrow x=\left(\frac{14}{7}\right)$

$\Rightarrow x=2$

The value of x and y are 2 and 3 respectively.