Answer:
a candy is $4
you have a $20 bill
1 candy = 4
2 candies = 8
3 candies = 12
4 candies = 16
5 candies = 20
you can buy 5 candies for $20.
Solutions
In Matrix we use initially based on systems of linear equations.The matrix method is similar to the method of Elimination as but is a lot cleaner than the elimination method.Solving systems of equations by Matrix Method involves expressing the system of equations in form of a matrix and then reducing that matrix into what is known as Row Echelon Form.<span>
Calculations
</span>⇒ <span>Rewrite the linear equations above as a matrix
</span>
⇒ Apply to Row₂ : Row₂ - 2 <span>Row₁
</span>
⇒ <span>Simplify rows
</span>
Note: The matrix is now in echelon form.
<span>The steps below are for back substitution.
</span>
⇒ Apply to Row₁<span> : Row</span>₁<span> - </span>5 Row₂
⇒ <span>Simplify rows
</span>
⇒ <span>Therefore,
</span>

<span>
</span>
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
Answer:
a+2b
Step-by-step explanation:
2(a+2b) -a-2b
2a+4b-a-2b
a+2b