Question

using elimination method slove this o.4× +o.3y=1.7 and 0.7×-0.2y=0.8​

Answer 1

$\tt{0.4x+0.3y=1.7}$

$\rightarrow\tt{4x+3y=17}$ _____(i)[multiplying by 10 on both sides]

$\tt{0.7x-0.2y=0.8}$

$\rightarrow\tt{7x-2y=8}$ _____(ii)[multiplying by 10 on both sides]

Now,

(i)×7= 28x+21y= 119

(ii)×4= 28x-8y = 32

(i)-(ii)

21y-(-8y)=119-32

29y=87

y=3

Putting the value of y=3 in eq. (i)

$\rightarrow\tt{4x+3×3=17}$

$\rightarrow\tt{4x+9=17}$

$\rightarrow\tt{4x=17-9}$

$\rightarrow\tt{4x=8}$

$\rightarrow\tt{x=2}$

Answer 2

Answer;

_____(i)[multiplying by 10 on both sides]

_____(ii)[multiplying by 10 on both sides]

Now,

(i)×7= 28x+21y= 119

(ii)×4= 28x-8y = 32

(i)-(ii)

21y-(-8y)=119-32

29y=87

y=3

Putting the value of y=3 in eq. (i)