Question

If x=-2 and x=-1/5 are the equation 5xsquare +px+r find p and r

Answer 1

if x = - 2

5 (-2) + p(-2) + r

-10 -2p + r  .... (1)

if x = -1/5

5 (-1/5) + p (-1/5) + r

-1 +5p -1 + r

-2 + 5p + r ....(2)

sub 1

-2p = 10 - r

p = 5 + r/2

sub in 2

-2 + 5 (5 +r/2) +r

-2 + 25 + 5r/2 +r

23