Question

if a-b=7and ab=9 then asquare+ b square =​

Answer 1

Answer:

a-b=7

ab=9

a-b=7

squaring both side,

(a-b)²=7²

a²+b²+2ab=49. (ab=9)

a²+b²+2(9)= 49

a²+b²+18=49

a²+b²=49-18

a²+b²=31

Answer 2

Answer:

$\boxed{\bf a^2 + b^2 =67}$

Step-by-step explanation:

$Given, \\ a - b = 7 \\ ab = 9 \\ a^2+b^2=? \\\\ \boxed{\bf(a-b)^2 = a^2 + b^2 - 2ab} \\\\7^2=a^2 + b^2 - 2(9) \\\\ 49 =a^2 + b^2 - 18 \\\\ a^2 + b^2 =49+18 \\\\ \boxed{\bf a^2 + b^2 =67}$