How do you solve the following linear system: #3x-y=23 , 8x=y+1 #?

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Answer 1 · 2018-05-25T09:37:37

The solution is #{(x=-22/5),(y=-181/5):}#

Proceed as follows :

#{(3x-y=23),(8x=y+1):}#

Rewrite equation #(2)#

#<=>#, #{(3x-y=23),(y-8x=-1):}#

Add equation #(1)# to equation #(2)#

#<=>#, #{(3x-y=23),(-5x=22):}#

#<=>#, #{(3x-y=23),(x=-22/5):}#

#<=>#, #{(y=3x-23=-66/5-23=-181/5),(x=-22/5):}#

graph{(3x-y-23)(8x-y-1)=0 [-61.95, 55.14, -56.8, 1.72]}

Answer 2 · 2018-05-25T09:46:57

Solution: # x =-4.4 , y = -36.2#

#3 x-y=23; (1) , 8 x=y +1 or 8 x -y =1 ; (2)#

Subtracting equation (2) from equation (1) we get,

# (3 x- y) - (8 x - y) =23 -1 # or

# 3 x- cancel y - 8 x + cancel y =22 # or

#-5 x= 22 :. x = -22/5 = -4.4# Putting #x = -22/5#

in equation (1) we get, #3*(-22/5) -y =23# or

# y = -66/5-23 or y= -181/5 =-36.2 #

Solution: # x =-4.4 , y = -36.2# [Ans]