Question

What are the rational roots for the polynomial shown below?
x³ + 5x²-8r-20=0

Answer 1

`x ^(3) + 5x {}^(2) - 8 r - 20 = 0 \\ x { }^(3) + 5x {}^(2) - 8r - 20(x {}^(3) + 5x {}^(2) ) = 0 - (x {}^(3) + 5x {}^(2) ) \\ - 8r - 20 = - (x {}^(3) + 5x {}^(2) ) \\ \\ - 8r - 20 + 20 = - (x {}^(3 ) + 5x {}^(2) ) + 20 \\ \\ - 8r = x {}^(3) - 5x {}^(2) + 20 \\ \\`

hope it is helpful