### Home > GB8I > Chapter 1 Unit 1 > Lesson INT1: 1.1.1 > Problem1-9

1-9.

Simplify each expression.

1.  $−42+(−17)$

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

$−59$

1.  $8−(−9)$

Subtracting a negative is the same as adding a positive. Think of this as $8+9$.

1.  $8(−9)$

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

$−72$

1.  $−42\div(−7)$

The rules for division are the same as the rules for multiplication.

1.  $−2(−3)(−4)$

Multiplying two negatives makes a positive.

$−2(−3)=6$       So
$−2(−3)(−4)=6(−4)$

Multiplying a positive and a negative makes a negative.

$6(−4)=−24$

$−24$

1.  $−18−7$

Subtraction is like adding a negative. Refer to part (a) to see the process.

1.  $(−5)^2$

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

$25$

1.  $−5^2$

Think of this as $−(5^2)$
which is $−(5)(5)$.

1.  $\sqrt { 49 }$

What positive number multiplied by itself is $49$?

$7$