Question

factorise the following a²-9b²​

Answer 1

$solve = ( {a}^{2}) - {3}^{2} {b}^{2} \\ theory: \: difference \: of \: two \: perfect \: squares \: \\ proof = (a + b) \times (a - b) = \\ = {a}^{2} - ab + ba - {b}^{2} = \\ = {a}^{2} - ab + ab - {b}^{2} = \\ = {a}^{2} - {b}^{2} \\ := ab = ba \: is \: the \: commutative \: property \: \\ of \: multiplication \\ := - ab + ab = 0 \: therefore \: eliminted \\ \: from \: the \: expression \: \\ = 9 \: is \: the \: square \: of \: 3 \\ = {a}^{2} \: is \: the \: square \: of \: {a}^{1} \\ = {b}^{2} \: is \: the \: square \: of \: {b}^{1} \\ = (a + 3b) \times (a - 3b)$

hope it's help you...

please mark as brainleist and follow me...