PEMDAS, or Please Excuse My Dear Aunt Sally, is the mnemonic device for order of mathematical operations used to solve algebraic equations. It represents parentheses, exponents, multiplication, division, addition and subtraction. Equations cannot just be solved left-to-right because the proper order of operations must be observed.
Continue ReadingUse the example equation (4x + 3x) - 5 + 4 - 10x/5 = 4 as a starting point. The terms 4x and 3x are in parentheses so these should be added first.
To avoid confusion, the terms inside parentheses are solved first and the exponent is applied to the variable. The coefficient is not affected.
Dividing 10x by 5 yields 2x. The equation is simplified to 7x - 5 + 4 - 2x = 4.
Like terms are variables of the same degree or power to which they are raised. 7x - 2x leaves 5x, and adding -5 and 4 leaves -1.
After all like terms have been simplified, the equation is 5x - 1 = 4. Adding 1 to both sides yields 5x = 5, and x is 1. After solving, check the original equation.