What you’ll learn
Use point-slope form.
Key idea
Subtract a negative anchor by adding its magnitude; keep the given slope.
Subtract each signed coordinate; a nonzero-x point output is not automatically the intercept.
Worked example
Enter the exact value or ordered values in the format requested below.
Write a genuine point-slope equation with slope -4 through (-3,4); keep point-slope structure.
- Point-slope form is y-y_1=m(x-x_1), preserving each signed coordinate.
- Substitution of (-3,4) makes both sides zero in y-4=-4(x+3); its slope is -4 and intercept -8.
Answer: y-4=-4(x+3)
Quick Check
Evaluate a worked attempt at use point-slope form, identify the first invalid step, and provide the correction.
For slope -4 through (2,-4), Step 1 uses y-y_1=m(x-x_1). Step 2 inserts y-4=-4(x-2). Identify first invalid step and correct the point-slope equation.