Work Step by Step
In order to solve this algebraic expression, we must isolate the variable. A variable is the letter in the problem (for instance, in the equation 2x=10, x is the variable). In the expression -4=2/9d, d is being multiplied by a fraction, which we must cancel out. In order to cancel out a fraction being multiplied by a variable, we multiply both sides of the equation by the reciprocal of the fraction, which is the fraction flipped upside down. (For instance, the reciprocal of ⅖ is 5/2). Thus, we multiply both sides of the equation by 9/2 to obtain that d=-18. When we plug -18 into the original equation and simplify, we get that, so the solution is correct.