Question

If a+b = 10 and a-b = 6 then find the value of ab​

Answer 1

-0.641

-9.359

Step-by-step explanation:

a+b = 10. Eq 1

ab = 6. Eq 2

From eq 1

a = 10 - b. Eq 3

From eq 3 on eq 2

(10-b) (b) = 6

10b - b^2 = 6

-b^2 + 10b - 6 = 0

b = (-10+-√{(10^2)-(4*-1-6)}) / (2*-1)

b = (-10 +-√{100-24)) / -2

b = (-10 +- √76) / -2

b = (10 +- 8.718)/-2

b1 = (10 - 8.718)/-2 = 1.282/-2 = -0.641

B2= (10 + 8.718)/2 = 18.718/-2 = -9.359

Answer 2

a + b = 10
a - b = 6

Add the equations together
2a = 16

Solve for a, divide 16 by 2.
a = 8

Then plug in a for one of the equations to get the value of b.

8 + b = 10

Subtract 8 from 10 to make b by itself.

b = 2

With a = 8 and b = 2, solve for ab

(8)(2) = 16.

ab = 16