If m represents the cost of a movie rental and g represents the cost of a video game rental, then we can write two equations:
2m+5g=$35
8m+3g=$38
Now if we subtract 5g from both sides of the first equation, we get
2m=$35-5g
Then, dividing by 2, we get
m=$17.50-2.5g.
Now substitute into the second equation to get
8($17.50-2.5g)+3g=$38
Distribute to get
$140-20g+3g=$38
$140-17g=$38
Add 17g-$38 to each side to get
$140-$38=17g
17g=$102
g=$6
Substitute back into the first equation to get
2m+5($6)=$35
2m+$30=$35
Subtract $30 from both sides to get
2m=$5
Divide by 2 to get
m=$2.50
So we have that a movie rental costs $4.75, and a video game rental costs $5.10. We check our work by substituting into both equations.
2($2.50)+5($6)=$35
$5+$30=$35
This is correct, and
8($2.50)+3($6)=$38
$20+$18=$38.
This is also correct, so we have the correct values.
Jarom L.
This is categorized as Algebra 1. It is a safe assumption this student does not know how to use matrices and determinants, since that is a linear algebra concept.03/10/21