1.

Simplify (x+3) (x-3) (x+5) (x-5) using suitable formulas

Answer»

Answer:

x² - 34X + 225

Step-by-step EXPLANATION:

(x+3) (x-3) (x+5) (x-5)

[(x+3)(x-3)] * [(x+5)(x-5)]

By using identity: (a+b)(a-b) = a² - b²

{ In both [(x+3)(x-3)] and [(x+5)(x-5)] }

[(x+3)(x-3)] * [(x+5)(x-5)] = (x² - 3²) * (x² - 5²)

                                      = (x² - 9) * (x² - 25)

Now, by using identity: (a + m)(a + N) = a² + (m+n)a + mn

{ On (x² - 9)(x² - 25) }

(x² - 9)(x² - 25) = x² + [-9 + (-25)]x + (-9)(-25)

                        = x² + (-34)x + 225

(x² - 9)(x² - 25) = x² - 34x + 225

Note: (*) sign represents here for multiplication.

Hope this helps...


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