Properties of equality have nothing to do with it. The associative and commutative properties of multiplication are used (along with the distributive property and the fact of arithmetic: 9 = 10 - 1).
All of these problems make use of the strategy, "look at what you have before you start work."
1. = (4·5)·(-3) = 20·(-3) = -60 . . . . if you know factors of 60, you can do this any way you like. It is convenient to ignore the sign until the final result.
2. = (2.25·4)·23 = 9·23 = 23·10 -23 = 230 -23 = 207 . . . . multiplication by 4 can clear the fraction in 2 1/4, so we choose to do that first. Multiplication by 9 can be done with a subtraction that is often easier than using ×9 facts.
4. = (2·5)·12·(-1) = 10·12·(-1) = (-1)·120 = -120 . . . . multiplying by 10 is about the easiest, so it is convenient to identify the factors of 10 and use them first. Again, it is convenient to ignore the sign until the end.
5. = 0 . . . . when a factor is zero, the product is zero
Answer8 hours
Step-by-step explanation:
Answer:
A. 
B. 
Step-by-step explanation:
A. The area of the shaded region = area of the whole large square - area of the 4 smaller squares
= (5x*5x) - 4(4*4)
Area of shaded region = 
B. The expression, , is the difference of two perfect squares, 25x² and 64. Therefore, apply the rule of factoring difference of two perfect squares.
Thus, 
Therefore, the expression of the are of the shaded region can be expressed in factored form as:
