1.

If `x=4/3`is a root of the polynomial `f(x)=6x^3-11 x^2+k x-20 ,`find the value of `k`

Answer» x=a is root of f(x)
f(a)=0
f(4/3)=0
`6*(4/3)^3-11(4/3)^2+k(4/3)-20=0`
`6*64/27-11*16/9+4/3k-20=0`
`(384-176*3+9*4k-20*27)/27=0`
`384-528+36k-540=0`
`36k=1068-384`
`k=19`.


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