How do you solve the system y=2xy=2x and x+3y=-14x+3y=−14 using substitution?
1 Answer
Apr 17, 2017
Explanation:
"Label the equations"Label the equations
color(white)(xxxx)color(red)(y)=2xto(1)××y=2x→(1)
x+3color(red)(y)=-14to(2)x+3y=−14→(2)
"Substitute " color(red)(y)=2x" in " (2)Substitute y=2x in (2)
rArrx+(3xx2x)=-14⇒x+(3×2x)=−14
rArr7x=-14⇒7x=−14
"divide both sides by 7"divide both sides by 7
(cancel(7) x)/cancel(7)=(-14)/7
rArrx=-2
"Substitute this value into " (1)
y=(2xx-2)=-4
color(blue)"As a check"
"substitute values for x and y in " (2)
-2+(3xx-4)=-2-12=-14to" true" graph{(y-2x)(y+1/3x+14/3)=0 [-10, 10, -5, 5]}
rArr" point of intersection is " (-2,-4)
