Question

The coefficient of 'x' in the expansion of $(x+3{)}^3$ is

• A. 1
• B. 9
• C. 18
• D. 27

Answer 1

The correct option is D 27

$(x+3{)}^3=x^3+3^3+3x(3\left)\right(x+3)$ $\left[using\right(a+b{)}^3=a^3+b^3+3ab(a+b)]$
$(x+3{)}^3=x^3+27+9x(x+3)$
$(x+3{)}^3=x^3+27+9x^2+27x$
Hence, the coefficient of $x$ in $(x+3{)}^{3}is27.$