Question

Simplify the expression (h+ k)²-(h - k)².

Hence, by substituting a suitable value of h and
of k, find the value of 165²- 35².

Answer 1

To simplify the expression (h+ k)²-(h - k)², we can use the difference of squares formula:
(h+ k)²-(h - k)² = (h+ k+ h- k)(h+ k- h+ k) = 4hk.

Substituting h=15 and k=5 into the expression gives us 4(15)(5) = 4*75 = 300. Thus, the value of 165²- 35² is equal to 300.