### Home > CC4 > Chapter 1 > Lesson 1.1.1 > Problem1-9

1-9.

Simplify each expression. Homework Help ✎

1. $- 42 + ( - 17 )$

• Because both numbers are negative, you can add them. Don't forget to make the answer negative.

• −59

1. $\quad 8 - ( - 9 )$

• Subtracting a negative is the same as adding a positive. This is the same problem as 8 + 9.

1. $8 ( - 9 )$

• Multiply the numbers. Because there is only one negative number, the final answer will be negative.

• −72

1. $- 42 \div ( - 7 )$

• The rules for dividing negative numbers are the same as the rules for multiplying them.

1. $- 2 ( - 3 ) ( - 4 )$

• Multiplying two negative numbers gives a positive number.

• −2(−3) = 6 So −2(−3)(−4) = 6(−4)

• Multiplying a positive and a negative makes a negative.

• 6(−4) = −24

• −24

1. $-18-7$

• Subtracting is the same as adding a negative number. Refer to part (a).

1. $( - 5 ) ^ { 2 }$

• Because the exponent is outside the parentheses, think of this as (−5)(−5).

• 25

1. $-5^2$

• Think of this as −(5²) which is −(5)(5).

1. $\sqrt { 49 }$

• What positive number multiplied by itself is 49?

• 7