Question

If a + b = 25 and a2 + b2 = 225, then find ab.

Answer 1

(a+b)^2 = 25^2

a^2 + b^2 + 2ab = 625

225 + 2ab = 625

2ab = 625 - 225 = 400

ab = 400/2 = 200

Answer 2

Answer:

The value of ab is 200.

Step-by-step explanation:

Given information:a + b = 25 and a² + b² = 225.

Using algebraic property

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

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

$(25)^2=(225)+2ab$

$625-225=2ab$

$400=2ab$

Divide both side by 2.

$200=ab$

Therefore the value of ab is 200.