Math Help
posted by TO: Mathmate on .
This is a substitution equation. Would that change the steps that you did?
Y=3x+1
Y=5x3
Answer says x=2 and y=7
Please explain steps. Thanks
math help  MathMate, Monday, April 23, 2012 at 10:25pm
Y=3x+1 ...(1)
Y=5x3 ...(2)
By comparison of (1) and (2), we conclude that
3x+1=Y=5x3
3x+1=5x3
solve for x to get
2x=4
x=2
Put x=2 in (1) to get
Y=3(2)+1=7
Check:
put x=2 in (2) to get
Y=5*23=7
If your program gives x=2 and y=7, there must be a typo somewhere. Check your post

y = 3 x + 1
y  1 = 3 x Divide both sides by 3
( y  1 ) / 3 = x
x = ( y  1 ) / 3
y = 5 x  3
y = 5 * ( y  1 ) / 3  3
y = ( 5 / 3 ) * ( y  1 )  3
y = 5 y / 3  5 / 3  3
y = 5 y / 3  5 / 3  9 / 3
y = 5 y / 3  14 / 3
y  5 y / 3 =  14 / 3
3 y / 3  5 y / 3 =  14 / 3
 2 / 3 y =  14 / 3 Multiply both sides by  3
2 y = 14 Divide both sides by 2
y = 14 / 2
y = 7
x = ( y  1 ) / 3
x = ( 7  1 ) / 3
x = 6 / 3
x = 2
x = 2 , y = 7
Or very simply :
y = 3 x + 1
y = 5 x  3
3 x + 1 = 5 x  3
3 x  5 x =  3  1
 2 x =  4 Divide both sides by  2
 2 x /  2 =  4 /  2
x = 2
y = 3 x + 1
y = 3 * 2 + 1 = 6 + 1 = 7
y = 5 x  3
y = 5 * 2  3 = 10  3 = 7
x = 2 , y = 7