We can solve quadratic equations in excel by inputting an equation that contains our variable (e.g. X), then we would define X using a formula. Thereafter, we would use this quadratic formula to solve for X using some given roots of the equation. This tutorial will teach use how to solve quadratic equation in excel.

Figure 1: Solving quadratic equations

Data for Solving Quadratic Equation

• To do this, we will type in our quadratic equation y = a + bx + cx^2 and also define the root of the variable “X” by typing this quadratic formula x0 = [-b ± SQRT(b^2 - 4ac]/2a

Figure 2: Quadratic formula

• We will now prepare a table for the roots of “X” which are “x1” and “x2”, and ascribing values for the variables in the equation of “X” which are “a, b, and c”

Figure 3: Table of roots

• We will type this formula into Cell B11 =(-B8+SQRT(B8^2-4*B7*B9))/(2*B7)

Figure 4a: Formula for the positive root of the equation

• We will now press the enter key

Figure 4b: Answer for the positive root of equation

• We will now repeat the same operation for “x2” by copying, pasting and changing “+” sign into a “–“minus sign in the formula in Cell B12 as =(-B8-SQRT(B8^2-4*B7*B9))/(2*B7)

Figure 5a: Formula for the negative root of the equation

• We will now press the enter key

Figure 5b: Solved quadratic equation