Question

2. If y = x3 + 2x + 5 and z = x2 + 7x + 1, what is 2y + z in terms of x? (A) 3x3 + 11x + 11 (B) 2x3 + x2 + 9x + 6 (C) 2x3 + x2 + 11x + 11 (D) 2x3 + 2x2 + 18x + 12

Answer 1

the given equation is,

$y=x^3+2x+5$

and

$z=x^2+7x+1$

now the expression is,

2y + z

put the values,

$2(x^3+2x+5)+x^2+7x+1$$\begin{gathered} 2x^3+4x+10+x^2+7x+1 \\ 2x^3+x^2+11x+11 \end{gathered}$

thus, the correct answer is option C