# Thread: Maths help with equation of line and algebra?

1. ## Maths help with equation of line and algebra?

Maths help with equation of line and algebra?

point r is (10,0)
point s is (-9,2)
show tht length of rs is 3 root 5 not sure how to work out length of a line?

also..
x sqaured+2px+(3p+4)=0, p is a positive constant with real roots find the value of p
do i expand first?? plz help!!

2. Originally Posted by lilz2009
Maths help with equation of line and algebra?

point r is (10,0)
point s is (-9,2)
show tht length of rs is 3 root 5 not sure how to work out length of a line?

distance formula ...

$d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

also..
x sqaured+2px+(3p+4)=0, p is a positive constant with real roots find the value of p
do i expand first?

... use the discriminant test for roots

$b^2 - 4ac \geq 0$
ok?

3. im still not sure bout line
i got square root of 365 not 3 root 5 must ha worked out s wrongly in previous question
for p i got -4/3 is this right?

4. Originally Posted by lilz2009
im still not sure bout line
i got square root of 365 not 3 root 5 must ha worked out s wrongly in previous question
distance between (10,0) and (-9,2) is $\sqrt{365}$

sure you copied down the coordinates for r and s correctly?

for p i got -4/3 is this right?
how did you get that specific value for p?