Question

a+b =7 and ab=10 find the value of a-b

Answer 1

Hello here is your answer by Sujeet yaduvanshi ☝☝☝☝☝☝☝☝☝
a+b = 7, ab=10

we can use the property

(a+b)2-(a-b)2= 4ab

So,

(7)2-(a-b)2=4*10

49-(a-b)2 =40

(a-b)2 =49-40

(a-b)2=9

(a-b)=√9
(a-b)=3

that's all

Answer 2

$(x + y) {}^{2} = {x}^{2} + {y}^{2} + 2xy \\ 7 {}^{2} = x {}^{2} + {y}^{2} + 2(10) \\ 49 = {x}^{2} + {y}^{2} + 20 \\ {x}^{2} + {y}^{2} = 29 \\( x - y) {}^{2} = {x}^{2} + {y}^{2} - 2xy \\ (x - y) {}^{2} = 29 - 20 \\ (x - y) {}^{2} = 9 \\ (x - y) = 3$