Question

0.4x+0.3y=1.7, 0.7x-0.2y=0.8 solve method

Answer 1

multiplay both equation by 10
4x+3y=17 .......(1)
7x+2y=8..........(2)

(1)×2 and (2)×3


8x + 6y = 34
21x + 6y = 24

-13x = 10
x = - 10/13

Answer 2

0.4x+0.3y=1.7]×0.2
0.7x-0.2y=0.8]×0.3

0.08x+0.06y=0.34.........i
0.21x-0.06y=0.24...........ii

i+ii
0.29x=0.58
=> x=2
putting the value of x in 0.4x+0.3y=1.7
0.4x+0.3y=1.7
0.4×2+0.3y=1.7
0.8+0.3y=1.7
0.3y=1.7-0.8
y=0.9/0.3
y=3
[x=2,y=3] ans...