maths correlation and regression...urgent help needed...

1. if x and y satisfy the relationship y = -5 + 7x, the value of r is?

2. if the realtion between x and u is 3x + 4u + 7 = 0 and the coeffecient correlation between x and y is -0.6, then what is the correlation coeffecient between u and y? thnaks in advance....

1. we know, r = root bxy * byx

                        = root -5*-5

                        =root 25

                        =5 ans........

2. 3x+4u = -7 therefore c = 4/3

then, ruy = |c|rxy

                = |4/3|*-0.6

                =4/3 *-0.6

                = -0.8 ans......

thanks a lot...

1. Its impossible to know r with just regression equation b = r*sy/sx so without knowing standard deviation of x or y or snowing bxy we can't tell what r is byx here is 7 bxy is not given swati wrongly assumed the constant coeefficient a as byx and assumed it is equal to byx and correlation coefficient is always less than 1

2.in the second one for correlation we only take the signs of the3 relationship and not magnitude u = -0.75x - 1.75 so u and x are negatively correlated now x and y correlation is - so u and y correlation is 0.6 0.6