Need for $7.90 you purchased 8 total items ( pens and highlighters) from a local bookstore. each highlighter cost $1.09 and each pen cost $.68.write a system of equations that can be used to find how many of each you bought a) 8p+8h=7.90 and 1.09 + .68 = 7.90 b) h+p=8 and .68 + 1.09p=7.90c) p+h= 7.90 and .68 + 1.09h=8d) h+p =8 and 1.09 + .68p = 7.90

p=number of pens

h=number of highlighters

p+h=8

1.09h+0.69p=752

p+h=8

minus h from both sides

p=8-h

sub that for p

1.09h+0.69(8-h)=7.52

1.09h+5.52-0.69h=7.52

0.4h+5.52=7.52

minus 5.52 from both sides

0.4h=2

divide both sides by 0.4

h=5

sub back

h=8-p

5=8-p

minus 8 frm both sides

-3=-p

mltiply both sides by -1

3=p

3 pens you bought

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

homozygous. one is homozygous, while two is heterozygous.