A. (−13)+(−7)= b. (−15)− (−15)= c. (2)∙ (−13)= d. (−44)÷ (11)= e. (−3)+(−5)+(8) +(25)= f. 3+4=4

See answer below

Step-by-step explanation:

In this case, this is just sum, substraction and divisions using the properties or the signus. This is just basic operations using the negative and positive numbers.

To do this easily you just have to remember the following:

1. Numbers with same sign, must be summed and put the sign that have either number.

2. Numbers with different sign, must be substracted and then put the sign of the highest number.

3. If you have a multiplication or division:

- Same signs multiplied or dividied (Either positive or negative), result always positive.

- Different signs multiplied or dividied (positive and negative), result always negative.

Following this simple rules, you'll be able to solve almost any exercise of this.

Now, according to the rules above, let's solve the exercises:

A. (-13) + (-7)

In this case, you have two negative numbers, and one positive sign between them. Apply the 3rd rule. The negative sign remains and then:

-13 - 7

Now 1st rule applied, sum the numbers and let the same sign:

-13 - 7 = -20.

B. (-15) - (-15) = 0.

Applying 3rd rule and then 2nd rule, we have a subtration of -15 + 15.

C. (2) * (-13) = -26

Applying the 3rd rule, we have positive and negative, result always negative.

D. (-44) / 11 = -4

3rd rule applied.

E. (-3) + (-5) + 8 + 25 = 31

Applied 3rd and 1st rule.

I don't understand the f, but you can use the rules here and get the final answer of that one.

Hope this helps

$4034.40

the perimeter of the field is the sum of the lengths of the four sides:

47 yd + 158 yd + 47 yd + 158 yd = 410 yd

the cost of 3 ft (1 yd) of fence is 3×$3.28 = $9.84.

so the cost of jake's wood perimeter fance is

(410 yd) × ($9.84 /yd) = $4034.40

m∠a is 90°

m∠b is 40°