Question

Solve the following systems of equations:

0.4x + 0.3y = 1.7
0.7x − 0.2y = 0.8

Answer 1

The given system of equation i

0.4x + 0.3y = 1.7 ......(i)

0.7x − 0.2y = 0.8 .....(ii)

Multiplying both sides of (i) and (ii), by 10, we get

4x + 3y = 17  ....(iii)

7x - 2y = 8 ......(iv)

From (iv), we get

7x = 8 + 2y

`=> 7x (8 + 2y)/7`

Substituting `x = (8 + 2y)/7` in (iii) we get

`4((8+2y)/7) + 3y = 17`

`=> (32 + 8y)/7 + 3y = 17`

=> 32 + 29y = 17 x 7

=> 29y = 119 - 32

=> 29y = 87

`=> y = 87/29 = 3`

Putting y = 3 in `x = (8 + 2y)/7` we get

`x = (8 + 2 xx 3)/7`

`= (8 + 6)/7`

`= 14/7`

= 2

Hence, the solution of the given system of equation is x = 2, y = 3