Question

Solve by substitution x-y=-11 y+7=-2x

Answer 1

x - y = - 11   .............( 1 )

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

from equation ( 1 )

x - y = - 11

x   = -11 + y  ...........( 3)      

putting x in equation  ( 2 )

y + 7 = - 2 x  

y  + 7 = -2 ( -11 + y )             y + 7 = 22 - 2 y                       y + 2 y =22 - 7            

3 y = 15                  y = 15 / 3

putting value of y in equation 3

x   = -11+ ( 13 /5 )                       x = -33 /3 + 15 / 3         ( l.c.m)

x  = -17 / 5                      

check      

x = -11 + y

- 17 / 5 = -11 + 13 / 5

-17 /5   = -17 / 5