Write equations in standard form
key notes:
What is Standard Form?
A linear equation in Standard Form is written as:
Ax+By=C
where:
- A, B and C are integers
- A should be non-negative (A ≥ 0)
- x and y are variables
- No fractions or decimals are allowed
Why Use Standard Form?
- Useful for finding intercepts quickly
- Common in word problems and real-life situations
- Makes comparing equations easier
Converting from Slope-Intercept Form to Standard Form
Slope-Intercept Form:
y=mx+b
Steps:
- Move the x-term to the left side (so both x and y are on the same side).
- Remove fractions or decimals by multiplying through by the denominator.
- Make sure A≥0 and all coefficients are integers.
Example 1
Convert y=2x+3 to standard form:
Step 1: Move 2x to left:
−2x+y=3
Step 2: Multiply by -1 (to make A>0):
2x−y=−3
✅ Standard Form:
2x−y=−3
Example 2
Convert y=3/4x−2 to standard form:
Step 1: Move 3/4x to left:
−3/4x+y=−2
Step 2: Multiply all terms by 4 to clear fraction:
−3x+4y=−8
Step 3: Multiply by -1:
3x−4y=8
✅ Standard Form: 3x−4y=8
From Point-Slope Form to Standard Form
Point-Slope Form:
y−y1=m(x−x1)
Expand, simplify, and arrange into Ax+By=C
Key Rules for Standard Form
- A, B, C are integers (no fractions/decimals)
- A≥ 0
- Write x first, then y, then constant
Practice Problems
Convert to standard form:
- y=−3x+7
- y=2/5x+4
- y−3=5(x−2)
- y=0.5x−6
Learn with an example
Rewrite the following equation in standard form.
y= –10/7 x − 10
Rewrite the equation in standard form.
y = -10/7 x − 10
10/7x + y = -10 [ add 10/7 x to both sides ]
10x + 7y = -70 [ Multiply both sides by 7 ]
Rewrite the following equation in standard form.
y = -2x − 3
Rewrite the equation in standard form.
y = -2x − 3
2x + y = -3 Add 2x to both sides
Rewrite the following equation in standard form.
y = 2x + 10
Rewrite the equation in standard form.
y = 2x + 10
–2x + y = 10 Subtract 2x from both sides
2x − y = –10 Multiply both sides by –1
Let’s Practice!