Question

If a+b=7 and ab=10, find the value of (a²+b²)​

Answer 1

${(a + b)}^{2} = {a}^{2} + {b}^{2} + 2ab \\ {7}^{2} = {a}^{2} + {b}^{2} + 20 \\ 49 - 20 = {a}^{2} + {b}^{2} \\ {a}^{2} + {b}^{2} = 29$