Here is a model I have made (I'm not a great artist). There are 42 circles in total, placed in 7 columns. Each column has 6 circles. This model represents 42/7 by splitting 42 into 7 parts, which are the columns, and showing that each column has 6 circles, which is the answer to 42/7.
1) 2x-1 or x=1/2
2) 5a-16 or a=16/5
X-intercept = -3
y- intercept = -6