Question

If a - b = 3 and a2 + b2 = 25, then the value of ab is solution

Answer 1

The value of ab is 4.

Answer 2

The value of ab is 8.

Given - Equation

Find - Value of ab

Solution - Firstly we need to write the write the expanded form of expression (a² + b²). The expanded form of this expression is as follows -

a² + b² = (a - b)² + 2ab

Now, keeping the given values in expanded expression.

25 = 3² + 2ab

Solving the above formed equation to find the value of ab

Taking square of the value on Right Hand Side of the equation

25 = 9 + 2ab

Shifting 9 to Left Hand Side of the equation

25 - 9 = 2ab

Performing subtraction on Left Hand Side of the equation

16 = 2ab

Shifting 16 to denominator on other side of the equation

ab = 16÷2

Performing Division

ab = 8

Hence, the value of ab is 8.

#spj2