Question

sabiendo que a+b=-9. y. a(b)=15. calcular a²+b²​

Answer 1

Recuerda que:

${(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2}$

Reemplazando:

${(9)}^{2} = {a}^{2} + 2(15) + {b}^{2} \\ {a}^{2} + {b}^{2} = 81 - 30 \\ {a}^{2} + {b}^{2} = 51$