Question

if a+b= 7andab=10 find the value of (a-b)​

Answer 1

Answer:

3

Step-by-step explanation:

Given, a+b =7 and ab=10

we know,

(a+b)^2 = a^2 + b^2 + 2ab

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

i.e. (7)^2 - 2(10) = a^2 + b^2

49 - 20 = a^2 + b^2

=> a^2 + b^2 = 29

Therefore, (a-b)^2 = a^2 + b^2 -2ab

=> (a-b)^2 = 29 - 2(10)

=> (a-b)^2 = 9

=> a-b = 3.

Hope it helps you... :)

Answer 2

Answer:

(a+b)= 7

(a+b)^2=49

ab=10

(a+b)^2=a^2+b^2+2ab

49= a^2 +b^2 + 2×10

49 -20 = a^2 + b^2

a^2+b^2 =29

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

(a-b)^2=29-20

(a-b)=root 9

a-b = 3