Question

Find the value of a ² + b2, when a + b= 9 and ab=20​

Answer 1

Step-by-step explanation:

$a + b = 9 \\ (a + b) {}^{2} = 9 {}^{2} \\ a {}^{2} + b {}^{2} + 2ab = 81 \\ a { }^{2} + b {}^{2} + 2 \times 20 = 81 \\ a {}^{2} + b {}^{2} = 41$