SAT Question 1e7a1deb: Equivalent Expressions answer and explanation with Desmos solution

Choice B is correct. Substituting $4k+5r$ for $a$ and $7k-12r+3$ for $b$ in the expression $a-b$ yields $(4k+5r)-(7k-12r+3)$. This expression can be rewritten as $(4k+5r)+(-1)(7k-12r+3)$. By applying the distributive property, this expression can be rewritten as $4k+5r-7k+12r-3$, which is equivalent to $(4k-7k)+(5r+12r)-3$, or $-3k+17r-3$.