Question

5x-4y=19
x+2y=8
solve the simultaneous equation

Answer 1

Explanation:

Given Equations:

`5x-4y=19` Equation:1

`x+2y=8`

or,
`x=8-2y` Equation:2

Using Substitution Method, putting the value of 'x' in equation:1

`5x-4y=19`

`5(8-2y)-4y=19\\\\5(8)-5(2y)-4y=19\\\\40-10y-4y=19\\\\40-14y=19\\`

Subtracting '40' both side:

`-14y=19-40\\\\-14y=-21\\\\y=-21/-14\\\\y=1.5`

Putting the value 'y' in Equation 2 to get the value of 'x':

`x=8-2y`

`x=8-2(1.5)\\\\x=8-3.0\\\\x=5`

The values are:
`x=5` and
`y=1.5`

Answer 2

x= 5, y = 1.5

Explanation:

to solve the equation simultaneously using substitution method we say that let

5x-4y=19 ................................. equation 1

x+2y=8.................................... equation2

from equation 2

x+2y=8.................................... equation2

x = 8-2y................................. equation 3

subtitute for x = 8-2y in equation 1

5x-4y=19 ................................. equation 1

5(8-2y) -4y = 19

40 -10y -4y =19

collect the like terms

40 -19 = 10y + 4y

21= 14y

divide both sides by 14

21/14 = 14y/14

1.5 = y

therefore y= 1.5

put y=1.5 in equation 3

x = 8-2y................................. equation 3

x = 8 - 2(1.5)

x = 8 -3

x = 5

therefore x= 5, y = 1.5