Let's solve your system by substitution.
y
=
−
2
x
+
7
;
y
=
5
x
−
7
Step: Solve
y
=
−
2
x
+
7
for y:
y
=
−
2
x
+
7
Step: Substitute
−
2
x
+
7
for
y
in
y
=
5
x
−
7
:
y
=
5
x
−
7
−
2
x
+
7
=
5
x
−
7
−
2
x
+
7
+
−
5
x
=
5
x
−
7
+
−
5
x
(Add -5x to both sides)
−
7
x
+
7
=
−
7
−
7
x
+
7
+
−
7
=
−
7
+
−
7
(Add -7 to both sides)
−
7
x
=
−
14
−
7
x
−
7
=
−
14
−
7
(Divide both sides by -7)
x
=
2
Step: Substitute
2
for
x
in
y
=
−
2
x
+
7
:
y
=
−
2
x
+
7
y
=
(
−
2
)
(
2
)
+
7
y
=
3
(Simplify both sides of the equation)
Answer: x=2 and y=3
Given:
Entrance fee per student: $5(29)
Lunch costs: $4(29 + 6)
Bus fees: $25 + 8($2 + $3)
Total cost: 5(29) + 4(35) + 25 + 8(5)
To find:
The equivalent expressions of the total cost that use the properties of operations to simplify the math.
Solution:
We have,
Total cost = 5(29) + 4(35) + 25 + 8(5)
To simply this expression, we need to write 29 and 35 in the expand form or as the sum of their place values because it is easy to multiply a number with multiply of 10 and single digit.
Total cost = 5(20+9) + 4(30+5) + 25 + 40
Therefore, the correct option is B.
