Solve the system of linear equations x 2y 5 4x y 7 Solut

Solve the system of linear equations: -x + 2y = -5 4x + y = -7

Solution

The two given equations are:

-x+2y= -5 ------------(1)

4x+y= -7 --------------(2)

multiplying (1) by the coefficient of x in (2)[which is 4] and multiplying (2) by the coefficient of x in (1)[which is -1] we write the two equations as:

-4x+8y= -20 -------------(3)

-4x-y=7    ----------------(4)

adding (4) and (3)

7y= -13   => y= -13/7 --------------(5)

Taking the value of y from (5) and putting in (2) we get:

4x-13/7=-7 => 4x=-7+(13/7) => 4x=(-49+13)/7 => 4x= -36/7

=> x= -9/7 = -1.28 and

y= -13/7 = -1.85