Question

si (a+b)al cuadrado-(a-b) al cuadrado=8, halla ab

Answer 1

$(a + b) ^{2} - (a - b) ^{2} = 8 \\ { a}^{2} + 2ab + {b}^{2} - ({a}^{2} - 2ab + {b}^{2}) = 8 \\{ a}^{2} + 2ab + {b}^{2} - {a}^{2} + 2ab - {b}^{2} = 8 \\ 4ab = 8 \\ ab = \frac{8}{4} \\ ab = 2$