Solving Literal Equations
To beginning algebra students, literal equations, those involving more than one letter, often seem inherently more difficult to solve than simpler, univariate on es. But this isn’t so. The trick is to treat the extra letters like simple numerals using the same steps you would ordinarily. Solving equations is a matter of “undoing” what’s been done to the variable, using inverse operations, starting as far from the variable as possible. - Example 1 To solve 3(x+4)–8 = 19, we first undo subtracting 8 by adding 8, then divide by 3 to undo multiplying by 3, and finally subtract 4 to undo adding 4. The result is x = 5. [Note: we could first simplify by distributing 3 across (x+4) and adding like terms, but this would take four steps, not three.] If the letters a, b, and c were to replace 3, 4, and 19 in the same equation, we’d carry out exactly the same series of steps. This time we’d start with a(x+b)–8 = c. We’d then add 8, divide by a, then subtract b to get x = (c+8)/a – b. W...