math question again?

Question

y = 3x + 1
so y intercept would be
0 = 3x + 1
3x = -1
x = - 1/3
how do u get - 1/3 from 3x = -1 ??
so wut would the y intercept be if y = 2/3x + 6

0 = 2/3x + 6
2/3x = -6
then wut?

Answer 1

You are mixing up the y-intercept and the x-intercept. To find the x-intercept, you set y = 0. To find the y-intercept, you set x = 0.

0 = 3x + 1
0 - 1 = 3x + 1 - 1
-1 = 3x
-1 / 3 = 3x / 3
-1/3 = x
so, x-intercept is ( -1/3 , 0 )

y = 3(0) + 1 = 0 + 1 = 1
so, y-intercept is ( 0 , 1 )
-----------------------------------
0 = (2/3)x + 6
0 - 6 = (2/3)x + 6 - 6
-6 = (2/3)x
(3/2)(-6) = (3/2)(2/3)x
-18/2 = x
-9 = x
so, x-intercept is( -9 , 0 )

y = (2/3)(0) + 6 = 0 + 6 = 6
so, y-intercept is ( 0 , 6 )

Answer 2

If 3x= -1 then divide both sides by 3 getting: x= -1/3

if y= 2/3x + 6 the y-intercept is 6
The x-intercept would be 0 = 2/3x +6
2/3x= -6 Now multiply both sides by 3/2 getting
x = -6(3/2) = - 9