81x^2-49y^2

Round off 0.004488 to 3 significant figures

Round down 487.29973 to 3 decimal places

if a class interval is 235-239,what is the class width of the class interval?

Determine whether each of the following equations is an identity.

4(3x+1)=2(6x+2)

Determine whether each of the following equations is an identity.

-5(7-x)+3=5x-32