Question

Write the coefficient of $x^2$ in the expansion of $(x-2{)}^3$

Answer 1

We know, $(a-b{)}^3=a^3-b^3-3a^{2}b+3a{b}^2$

So, $(x-2{)}^3=(x{)}^3-(2{)}^3-3(x{)}^2\left(2\right)+3\left(x\right)(2{)}^2$

$(x-2{)}^3=x^3-8-6x^2+12x$

So, here we can see coefficient of $x^2$ is $-6$

$\therefore$ Required ansqer is $-6$