Try substituting numbers for x and simplifying each expression. 0 and 1 can give different results, so check them as well as other numbers.

These two expressions are not equivalent. (But if you had only used 0 you might have thought they were).

Multiply and simplify.

These two expressions are equivalent.

See part (a).

Remember that (x + 4)² means (x + 4)(x + 4) and multiply.

These two expressions are equivalent.

Simplify the first expression and compare. Be sure you read the hint in part (b).

Try substituting numbers for a and b.