Answer:
4a^2+4ab+b^2
Step-by-step explanation:
To find the square we multiply the expression with itself
(2a+b)×(2a+b) = 4a^2+4ab+b^2
The answer should be Twenty one
The first one ....i belive.
Since the 9 is greater than or equal to 5, we'll round our number up by adding 1 to the 3 in the hundreds place, making it a 4. And also by changing all digits to the right of this new 4 into zeros.
And our rounded number would be 400
