Question

If a and b are integers such that a2 − b2 = 100, what is the greatest possible value of a?

Answer 1

Answer:

26

Step-by-step explanation:

Question says that 'a' and 'b' are integers that implies we cannot have 'a' and 'b' in the form of decimals.

Now, lets expand the given equation:

$a^2-b^2=100$

$(a+b)(a-b)=100$

Lets say: $(a+b)=p$, $(a-b)=q$

Let us consider the factor pairs of 100.

$(1 \times 100), (2 \times 50), (4 \times 25), (5 \times 20), (10 \times 10), (20 \times 5), (25 \times 4), (50 \times 2), (100 \times 1)$

Only factor pair $(2,50)$ gives us the integer values of 'a' and 'b'.

$a+b=50$....equation  (1)

$a-b=2$........ equation (2)

adding equation 1 and 2, we get:

$2a=52$

$a=\frac{52}{2}=26$

$a-b=2$

Plugging the value of 'a' in the equation 2

$26-b=2$

$b=24$

So the greatest possible value of 'a' is 26.