3x + 3 - x + 4 = 21
3x - x = 2x
2x +3 +4 = 21
3 + 4 = 7
2x + 7 = 21
-7 -7
2x = 14
--- ----
2 2
x = 7
<span>y = 5(12) - 3(4) + 8
y = 60 - 12 + 8
y= 56</span>
Answer:
0.9 yd³
Step-by-step explanation:
Information given:
Length = 18 ft
Width = 1.5 ft
Height = 1 ft
What to find/do:
First, convert the measurement from feet to yards. (3 ft = 1 yard)
Length = 18 ft = 6 yd
Width = 1.5 ft = 0.5 yd
Height = 1 ft = 0.3 yd
Next, find the volume of the shape given. The volume would give us the amount of concrete to use in yards.
Formula for volume = L*W*H
Plug in the values into the formula
V = 6*0.5*0.3 = 0.9 yd³
0.9 cubic yard of concrete must be ordered to pour on the given section.
Area of the volume
Our system of equations is:
y = x - 4
y = -x + 6
We can solve this system of equations by substitution. We already have one equation solved for the variable y in terms of x, so we can substitute in this equivalent value for y into the second equation as follows:
y = -x + 6
x - 4 = -x + 6
To simplify this equation, we first are going to add x to both sides of the equation.
2x - 4 = 6
Next, we are going to add 4 to both sides of the equation to separate the variable and constant terms.
2x = 10
Finally, we must divide both sides by 2, to get the variable x completely alone.
x = 5
To solve for the variable y, we can plug in our solved value for x into one of the original equations and simplify.
y = x - 4
y = 5 - 4
y = 1
Therefore, your final answer is x = 5 and y = 1, or as an ordered pair (5,1).
Hope this helps!
Since both terms are perfect cubes, factor using the difference of cubes formula,
a
3
−
b
3
=
(
a
−
b
)
(
a
2
+
a
b
+
b
2
)
a
3
-
b
3
=
(
a
-
b
)
(
a
2
+
a
b
+
b
2
)
where
a
=
x
2
a
=
x
2
and
b
=
y
b
=
y
.
(
x
2
−
y
)
(
(
x
2
)
2
+
x
2
y
+
y
2
)
(
x
2
-
y
)
(
(
x
2
)
2
+
x
2
y
+
y
2
)
Multiply the exponents in
(
x
2
)
2
(
x
2
)
2
.
