Symbol
Problem
$21\right)$ Correct the following. Each carries % mark. $1$ Error form Write its correct form $\left(x-y\right)^{2}=x^{2}+2xy+y^{2}$ $1$ $16x=-5,$ $3x=3-5=2$ $2.$ $\left(2x--$ $5$ $\right)\left(x$ $+$ $2\right)$ $=$ $2x$ $2$ $-10$ $3$ $-$ $2n+aA3$ $→=2a+b$ $a$ $54$ $\dfrac {\left(3x^{3}\right)^{2}-9x^{3}} {40^{3}+4a^{3}=0}$ $6.$ $\dfrac {\left(4x\right)^{2}=4x^{2}} {4\left(x-10\right)=4x-10}$ $74$ $8$