Question

If a+b=7 and ab=10; find a-b​

Answer 1

Step-by-step explanation:

(a-b)²

(a+b)²-4ab

7²-4×10

49-40

9

since

(a-b)²=9

a-b=3

Answer 2

°•●Answer●•°

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

$\sf \rightarrow {a}^{2} + {b}^{2} + 2ab - 4ab$

$\sf \rightarrow {(a + b)}^{2} - 4ab \\ \\ \sf \rightarrow {(7)}^{2} - 4ab \\ \\ \implies \sf49 = 4(10) \\ \\ \sf \implies49 - 40 = 9$

$\sf \rightarrow {(a + b)}^{2} = 9 \\ \\ \sf \implies \: a - b = + - \sqrt{9}$

$\therefore \sf \: a - b = + - 3$

Hope it helps you...