What is the difference between the "substitution method" and the "linear combination method"?

Substitution takes a variable and substitutes it for another equivalent equation. Linear combination takes two equations and adds them in order to eliminate a variable

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!