Question

(3a+2.5b)^2=9a^2+6.25b^2+* Please help before Thursday

Answer 1

Step-by-step explanation:

We have (x + y)² = (x + y)(x + y) = x² + 2xy + y².

Let x be 3a and y be 2.5b.

Therefore (3a + 2.5b)²

= (3a)² + 2(3a)(2.5b) + (2.5b)²

= 9a² + 15ab + 6.25b².

Hence the '*' sign should be replaced with 15ab.