Solve the following linear system (substitution)

Question

Solve the following linear system (substitution) 

 

2x-5y=12

x+10y=-9

Answer 1

Hi Divya,

 

2x-5y =12...... eq 1

 

x+10y =-9

 

so x= -9-10y.....   eq 2,

 

substitute the value of x from eq 2 to eq 1, we get

 

2(-9-10y) -5y =12

 

-18-20y-5y=12

     -25y = 30

       y = -30/25 = -1.2

 

now sbbstitute the value of y in eq 2, we get

x= -9 -10(-1.2) = -9+12 = 3

check:

LHS of eq 1=2x-5y = 2*3-5*(-1.2)= 6+6=12=RHS

RHS of eq 2= -9-10(-1.2)= 3= LHS

Ans x=3, y= -1.2