The difference of two numbers, a and b, is 21. The difference of 5 times a and two times b is 18. What are the values of a and b
\(a-b=21 |\cdot(-2)\\ 5a-2b=18\\\\ -2a+2b=-42\\ \underline{5a-2b=18}\\ 3a=-24\\ a=-8\\\\ -8-b=21\\ b=-29\)
\(a-b=21 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\times (-2) \\
5a-2b=18 \\ \\
-2a+2b=-42 \\
\underline{5a-2b=18 \ \ \ \ \ \ \ } \\
5a-2a=18-42 \\ 3a=-24 \\
a=\frac{-24}{3} \\
a=-8 \\ \\
a-b=21 \\
-8-b=21 \\
-b=21+8 \\
-b=29 \\
b=-29\)
a=-8 and b=-29.