Question

find the value of a square + b square when a minus b is equal to 7 and a b is equal to 30 ​

Answer 1

a^2 + b^2 = 109

Step-by-step explanation:

${a}^{2} + {b}^{2} = ?$

$a - b = 7 \: \: and \: \: ab = 30$

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

${7}^{2} = {a}^{2} + {b}^{2} - 2 \times 30$

49 = a^2 + b^2 - 60

a^2 + b^2 = 60+49 = 109

a^2 + b^2 = 109