Microsoft Office Tutorials and References

In Depth Information

**Solving Simultaneous Equations**

Calculating the volume of a pyramid

Calculate the area of the base, multiply by the height, and then divide by 3. This formula

calculates the volume of a pyramid. It assumes cells named
width
(the width of the base),
length
(the

length of the base), and
height
(the height of the pyramid).

=(width*length*height)/3

Solving Simultaneous Equations

This section describes how to use formulas to solve simultaneous linear equations. The following

is an example of a set of simultaneous linear equations:

3x + 4y = 8

4x + 8y = 1

Solving a set of simultaneous equations involves finding the values for x and y that satisfy both

equations. For this set of equations, the solution is as follows:

x = 7.5

y = –3.625

The number of variables in the set of equations must be equal to the number of equations. The

preceding example uses two equations with two variables. Three equations are required to solve

for three variables (x, y, and z).

The general steps for solving a set of simultaneous equations follow. See Figure 10-3, which uses

the equations presented at the beginning of this section.

1.
Express the equations in standard form. If necessary, use simple algebra to rewrite the

equations such that the variables all appear on the left side of the equal sign. The two

equations that follow are identical, but the second one is in standard form:

3x –8 = –4y

3x + 4y = 8

2.
Place the coefficients in an
n x
n range of cells, where
n represents the number of

equations. In Figure 10-3, the coefficients are in the range I2:J3.

3.
Place the constants (the numbers on the right side of the equal sign) in a vertical range

of cells. In Figure 10-3, the constants are in the range L2:L3.