Write a system of equations to solve. 10. A woman's age is three years more than twice her son's age. The sum
of their ages is 84. How old is the son?
11. The length of a rectangle is three times its width. The perimeter of the
rectangle is 100 inches, What are the dimensions of the rectangle?
12. Benecio worked 40 hours at his two jobs last week. He earned $20 per
hour at his weekday job and $18 per hour at his weekend job. He
earned $770 in all. How many hours did he work at each job?
y
13. Choose one of Exercises 1-9 and graph its solution
Does the answer you found by substitution agree
with the answer you got by graphing?
graph #3

10: the son is 12

11. W = 12.5 inches    L: 37.5 inches

12.  25 hours at his weekday job and 15 hours at his weekend job.

hope you got 13 right! Also I don't really have a step-by-step explanation I kinda just did them in my head so be careful with them. Good Luck!  

Step-by-step explanation:

:P

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!

answer: the answer is one of

step-by-step explanation:   we are given to write a proper fraction where the whole is divided into an even number of equal parts less than ten, and an odd number of those parts exist.

an even number less than 10 may be one of 2, 4, 6 or 8. so, the whole may be one of these four evens.

now, an odd number of these parts must exist, so the numerator must be an odd number, one of 1, 3, 5 or 7. it cannot be 9 because then the fraction will become improper.

thus, our fraction may be one of the following