# hp 35s - Solving Linear Equation

A linear equation is an algebraic equation in which each term is either a constant or the product of a constant and (the first power of) a single variable. Linear equations can have one, two, three or more variables. A common form of a linear equation in the two variables x and y is

y = mx + b

where m and b designate constants and the variable y is multiplied by the constant 1, which as usual is not explicitly written.

Examples of linear equations in two variables:

y = -x + 5

y = 0.5x + 2

to solve a 2*2 simultaneous equation on the 35s, the equation is as follows:

-0.28x + 1.9396y = 682.48

x + 0.342y = 803.31

Keystrokes:

EQN

SHIFT Solve (when the 2*2 equation solver is shown)

0.28 +/- R/S

1.9395 R/S

682.48 R/S

1 R/S

0.342 R/S

803.31 R/S

and the correct answer for X is shown. Pressing down arrow shows the correct answer for Y. Make sure you clear the memories on the 35s before starting a 2*2 after having done a 3*3.