How do solve the following linear system?: #y= -2x + 1 , 8x + 3y= -9 #?
1 Answer
Jan 7, 2016
x = - 6 , y = 13
Explanation:
write the equations with labels on them- this helps when wedo operations on them.
y + 2x = 1 (1)
3y + 8x = - 9 (2)
to eliminate y multiply (1) by - 3
(- 3y) - 6x = - 3 (3)
now add (2) and (3 ) and y is eliminated.
2x = - 12
now substitute x = - 6 in (1) ( you could substitute in (2) if you wish )
y +
check: x= - 6 , y = 13 in (1)→ 13 + 2 (- 6) =13 - 12 =1 and equation is true.
check x = - 6 , y = 13 in (2) →3(13) + 8(- 6 ) = 39 - 48 = - 9 and equation is also true.