How do you figure out rational solutions

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

Use your knowledge of the binary number system to write each binary number as a decimal number. a) 1001 base 2= base 10 b) 1101 base 2 = base 10