The polynomial f(x) =2x\(^3\) + px+ qx - 5 has (x-1) as a factor and a remainder of 27 when divided by (x + 2), where p and q are constants. Find the values...
Assessment:WAEC SSCE - Further Mathematics - 2021Subject:Further Mathematics
The polynomial f(x) =2x\(^3\) + px+ qx - 5 has (x-1) as a factor and a remainder of 27 when divided by (x + 2), where p and q are constants. Find the values of p and q.
Reading the polynomial as \(f(x)=2x^{3}+px^{2}+qx-5\) (the two linear terms in the printed stem are a typographical slip for a quadratic and a linear term).
Since \((x-1)\) is a factor, \(f(1)=0\):
\[2+p+q-5=0\Rightarrow p+q=3\quad(\text{i})\]
The remainder is \(27\) when divided by \((x+2)\), so \(f(-2)=27\):
Reading the polynomial as \(f(x)=2x^{3}+px^{2}+qx-5\) (the two linear terms in the printed stem are a typographical slip for a quadratic and a linear term).
Since \((x-1)\) is a factor, \(f(1)=0\):
\[2+p+q-5=0\Rightarrow p+q=3\quad(\text{i})\]
The remainder is \(27\) when divided by \((x+2)\), so \(f(-2)=27\):