Thread: slope intercept

hi, could you please help with this problem explaining the reasoning behind it?
I'm confused! Thank you.




In the x-y plane what is the y-intercept of line k?

1) the slope of line k is 3 times its y-intercept

2) the x-intercept of line k is -1/3

A) Statement 1) alone is sufficient
B) Statement 2) alone is sufficient
C) Statements 1) and 2) together are sufficient
D) Each statement alone is sufficient
E) Statement 1) and 2) together are not sufficient

Originally Posted by simone

hi, could you please help with this problem explaining the reasoning behind it?
I'm confused! Thank you.




In the x-y plane what is the y-intercept of line k?

1) the slope of line k is 3 times its y-intercept

2) the x-intercept of line k is -1/3

A) Statement 1) alone is sufficient
B) Statement 2) alone is sufficient
C) Statements 1) and 2) together are sufficient
D) Each statement alone is sufficient
E) Statement 1) and 2) together are not sufficient

in the equation of a line: y = mx + b. b gives the y-intercept.

from (1) we know that, for the line k: y = (3b)x + b
from (2) we know that, for the line k: y = 0, when x = -1/3 .....this actually does not give us anymore information that (1) did, we could have figured this out from (1).

we cannot solve for b based on these two statements, there are too many unknowns. therefore, E is the answer