Standard Form
Site: | Saylor Academy |
Course: | GKT101: General Knowledge for Teachers – Math |
Book: | Standard Form |
Printed by: | Guest user |
Date: | Tuesday, 20 May 2025, 8:15 AM |
Description
When a linear equation is written in standard form, both variables x and y are on the same side of the equation. Watch this lecture series and practice converting equations to standard form.
Intro to linear equation standard form
Source: Khan Academy, https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:forms-of-linear-equations#x2f8bb11595b61c86:standard-form This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.
Graphing a linear equation: 5x+2y=20
Clarifying standard form rules
Converting from slope-intercept to standard form
Graph from linear standard form - Questions
1. Graph \(12 x-9 y=36\).
2. Graph \(3 x+4 y=12\).
3. Graph \(x+3 y=6\).
4. Graph \(-14 x+21 y=84\).
Answers
1. This is a linear equation given in standard form: \(A x+B y=C\). A common way of graphing an equation of this form is to find the \(x\)- and \(y\)-intercepts of the graph.
To find the \(y\)-intercept, let's substitute \(x=0\) into the equation and solve for \(y\):
\(\begin{aligned}
12 x-9 y &=36 \\
12 \cdot 0-9 y &=36 \\
-9 y &=36 \\
y &=-4
\end{aligned}\)
So the \(y\)-intercept is \((0,-4)\).
To find the \(x\)-intercept, let's \(y=0\) into the equation and solve for \(x\):
\(\begin{aligned}
12 x-9 y &=36 \\
12 x-9 \cdot 0 &=36 \\
12 x &=36 \\
x &=3
\end{aligned}\)
So the \(x\)-intercept is \((3,0)\).
We can graph the linear equation using these two points, as shown below:
2. This is a linear equation given in standard form: \(A x+B y=C\). A common way of graphing an equation of this form is to find the \(x\)- and \(y\)-intercepts of the graph.
To find the \(y\)-intercept, let's substitute \(x=0\) into the equation and solve for \(y\):
\(\begin{array}{r}
3 x+4 y=12 \\
3 \cdot 0+4 y=12 \\
4 y=12 \\
y=3
\end{array}\)
So the \(y\)-intercept is \((0,3)\).
To find the \(x\)-intercept, let's \(y=0\) into the equation and solve for \(x\):
\(\begin{array}{r}
3 x+4 y=12 \\
3 x+4 \cdot 0=12 \\
3 x=12 \\
x=4
\end{array}\)
So the \(x\)-intercept is \((4,0)\).
We can graph the linear equation using these two points, as shown below:
3. This is a linear equation given in standard form: \(A x+B y=C\). A common way of graphing an equation of this form is to find the \(x\)- and \(y\)-intercepts of the graph.
To find the \(y\)-intercept, let's substitute \(x=0\) into the equation and solve for \(y\):
\(\begin{array}{r}
x+3 y=6 \\
0+3 y=6 \\
3 y=6 \\
y=2
\end{array}\)
So the \(y\)-intercept is \((0,2)\).
To find the \(x\)-intercept, let's \(y=0\) into the equation and solve for \(x\):
\(\begin{array}{r}
x+3 y=6 \\
x+3 \cdot 0=6 \\
x=6
\end{array}\)
So the \(x\)-intercept is \((6,0)\).
We can graph the linear equation using these two points, as shown below:
4. This is a linear equation given in standard form: \(A x+B y=C\). A common way of graphing an equation of this form is to find the \(x\)- and \(y\)-intercepts of the graph.
To find the \(y\)-intercept, let's substitute \(x=0\) into the equation and solve for \(y\):
\(\begin{aligned}
-14 x+21 y &=84 \\
-14 \cdot 0+21 y &=84 \\
21 y &=84 \\
y &=4
\end{aligned}\)
So the \(y\)-intercept is \((0,4)\).
To find the \(x\)-intercept, let's \(y=0\) into the equation and solve for \(x\):
\(\begin{array}{r}
-14 x+21 y=84 \\
-14 x+21 \cdot 0=84 \\
-14 x=84 \\
x=-6
\end{array}\)
So the \(x\)-intercept is \((-6,0)\).
We can graph the linear equation using these two points, as shown below:
Convert linear equations to standard form - Questions
1. What is \(y-8=3(x+1)\) written in standard form?
Choose 1 answer:
A. \(y-8=3 x+3\)
B. \(y=3 x+11\)
C. \(-3 x+y-11=0\)
D. \(-3 x+y=11\)
2. What is \(y=\frac{4}{5} x+2\) written in standard form?
Choose 1 answer:
A. \(-\frac{4}{5} x+y-2=0\)
B. \(y=\frac{4}{5}\left(x+\frac{5}{2}\right)\)
C. \(5 y=4 x+10\)
D. \(-4 x+5 y=10\)
3. What is \(y+5=7(x-8)\) written in standard form?
Choose 1 answer:
A. \(x-7 y=-61\)
B. \(7 x+y=-61\)
C. \(-7 x+y=-61\)
D. \(x+7 y=-61\)
4. What is \(y=-\frac{3}{10} x-8\) written in standard form?
Choose 1 answer:
A. \(10 x+3 y=-80\)
B. \(10 x-3 y=-80\)
C. \(-3 x+10 y=-80\)
D. \(3 x+10 y=-80\)
Answers
1. D. \(-3 x+y=11\)
Standard linear equations are in the general form \(A x+B y=C\) where \(A\), \(B\), and \(C\) are constants.
Usually, \(A\), \(B\), and \(C\) are integers.
\(y-8=3(x+1)\) | |
\(y-8=3 x+3\) | Distribute. |
\(y=3 x+11\) | Collect constants. |
\(-3 x+y=11\) | Bring to standard form. |
\(y-8=3(x+1)\) written in standard form is \(-3 x+y=11\).
2. D. \(-4 x+5 y=10\)
Standard linear equations are in the general form \(A x+B y=C\) where \(A\), \(B\), and \(C\) are constants.
Usually, \(A\), \(B\), and \(C\) are integers.
\(y=\frac{4}{5} x+2\) | |
\(5 y=4 x+10\) | Multiply by denominator. |
\(-4 x+5 y=10\) | Bring to standard form. |
\(y=\frac{4}{5} x+2\) written in standard form is \(-4 x+5 y=10\).
3. C. \(-7 x+y=-61\)
Standard linear equations are in the general form \(A x+B y=C\) where \(A\), \(B\), and \(C\) are constants.
Usually, \(A\), \(B\), and \(C\) are integers.
\(y+5=7(x-8)\) | |
\( y+5=7 x-56\) | Distribute. |
\(y=7 x-61\) | Collect constants. |
\(-7 x+y=-61\) | Bring to standard form. |
\(y+5=7(x-8)\) written in standard form is \(-7 x+y=-61\).
4. D. \(3 x+10 y=-80\)
Standard linear equations are in the general form \(A x+B y=C\) where \(A\), \(B\), and \(C\) are constants.
Usually, \(A\), \(B\), and \(C\) are integers.
\(y=-\frac{3}{10} x-8\) | |
\(10 y=-3 x-80\) | Multiply by denominator. |
\(3 x+10 y=-80\) | Bring to standard form. |
\(y=-\frac{3}{10} x-8\) written in standard form is \(3 x+10 y=-80\).