Question

Solve the following simultaneous equation by substitution method : 1.8x+y=12,1.4x+1.4y=11.2​

Answer 1

Step-by-step explanation:

y=12-1.8x

1.4x+1.4(12-1.8x)=11.2

1.4x + 16.8 - 2.52x=11.2

5.6=1.12x

x=5

y = 12- 1.8×5

y= 12- 9

y=3

Answer 2

Step-by-step explanation:

Given:-

simultaneous equations 1.8x+y=12,1.4x+1.4y=11.2

To find:-

Solve the following simultaneous equation by substitution method : 1.8x+y=12,1.4x+1.4y=11.2

Solution:-

Given equations are

1.8x+y=12-----(1)

1.4x+1.4y=11.2-----(2)

From (1) we have , y=12-1.8x-----(3)

substitute the value of y in (2)

=>1.4x+1.4(12-1.8x)=11.2

=>1.4x+16.8-2.52x=11.2

=> 1.4x-2.52x=11.2-16.8

=>-1.12x=-5.6

=>1.12x=5.6

=>(112/100)x=(56/10)

=>x=(56/10)×(100/112)

=>x=(56×100)/(10×112)

=>x=5

The value of x=5

Substitute the value of x in (3)

=>y=12-1.8(5)

=>y=12-9

=>y=3

The value of y=3

Answer:-

Solution for the given equations is (5,3)

Check:-

1.8x+y=12,

LHS=1.8(5)+3

=>9+3=12

LHS=RHS

1.4x+1.4y=11.2

LHS=1.4(5)+1.4(3)

=>7+4.2

=>11.2

LHS=RHS