Question

Given that a+b=10 and a^2-b^2=40,find the value of a-b

Answer 1

★ LINEAR REDUCTION ★

Given equation :

a + b = 10

And , a² - b² = 40

a + b ( a - b ) = 40

Using above relationship :

a - b = 40 / ( a + b )

a - b = 40 / 10 = 4

★✩★✩★✩★✩★✩★✩★✩★✩★✩★✩★

Answer 2

Given a + b = 10 then a = 10 - b ---- (1).

Given a^2 - b^2 = 40 

          (10 - b)^2 - b^2 = 40  ( From (1))

         100 + b^2 - 20b - b^2 = 40

         -20b = -60

             b = 3.


Substitute b = 3 in (1), we get

a = 10 - 3

  = 7


Then a - b = 7 - 3 = 4.


Hope this helps! :)