Like terms are terms that contain the same variables raised to the same power. As such in your equation you would combine the <em>4x</em> and the <em>-x</em> because they contain the same variable (x). To combine these terms you simply add <em>4x + - x</em>, which can be written as <em>4x - x</em>. The product of this is <em>3x. </em>Because there is a <em>3</em> on its own with no other like terms to add to it the it, the simplified version of this equation would be <em>3x+3</em>.
