Question

69. If a2 + b2 = 10 and ab= -3, find the value of a-b.
(1) 4
(2) 3
(3) 7
(4) √7​

Answer 1

Answer:

4

Step-by-step explanation:

a2 +b2 -2ab =(a-b)2

10 -2(-3) =(a-b)2

(a-b)2 = 16

a-b = 4

Answer 2

Answer:

$(a - b) {}^{2} = (a + b) {}^{2} - 4ab$

$this \: the \: formula \: to \: use \:$

$(a - b) {}^{2} = (a {}^{2} + b {}^{2} + 2ab) - 4ab$

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

$(a - b ) {}^{2} = 10 - 2 \times - 3$

$(a - b) {}^{2} = 10 + 6$

$(a - b) {}^{2} = 16$

$a - b = \sqrt{16}$

$a - b = 4$