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<p>Maths Formula:</p> <ul> <li>(x+a) (x+b) = x<sup>2</sup>+ (a+b) x + ab</li> <li>(a+b)<sup>2 </sup>= a<sup>2</sup>+ 2ab + b<sup>2</sup></li> <li>(a-b)<sup>2</sup> = a<sup>2 </sup>- 2ab + b<sup>2</sup></li> <li>a<sup>2</sup>-b<sup>2 </sup>= (a+b) (a-b)</li> </ul> <p> </p>