StatGardenREF. DESK
Calculators/Maths/Synthetic division
Maths

Synthetic division calculator

Divides a polynomial by (x − r) and returns the quotient and remainder.

What this calculator does

Synthetic division works out divides a polynomial by (x − r) and returns the quotient and remainder. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.

The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.

The formula

FormulaBring down the leading coefficient; each next value = previous result × r + next coefficient; the last value is the remainder

The inputs explained

FieldWhat to enter
Coefficients, highest degree firstA list of numbers, separated by commas or spaces.
Divide by (x − r): value of rA number. Starts at 1.

Worked examples

Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.

How the answer changes with divide by (x − r): value of r

Every other input is held at the calculator’s starting values while divide by (x − r): value of r varies. Select any row to load that scenario into the calculator.

How the answer changes with divide by (x − r): value of r
Divide by (x − r): value of rQuotientRemainderIs (x − 0.50) a factor?
0.51.00x^2 − 5.50x + 8.25-1.875No
0.751.00x^2 − 5.25x + 7.06-0.7031No
11.00x^2 − 5.00x + 6.000Yes: remainder is 0
1.51.00x^2 − 4.50x + 4.250.3750No
21.00x^2 − 4.00x + 3.000Yes: remainder is 0
31.00x^2 − 3.00x + 2.000Yes: remainder is 0