Use a spreadsheet or an equivalent technology to construct a table of values from a formula, including two-by-two tables for formulas with two variable quantities.

A mobile phone plan charges a base fee of $35 per month plus $0.15 per megabyte of data used. The total monthly cost is given by the formula \( C = 35 + 0.15m \), where \( m \) is the number of megabytes used and \( C \) is the cost in dollars. Construct a table showing the total monthly cost for data usage of 50, 100, 150, 200, 250 and 300 megabytes.

A mobile phone plan charges a monthly base fee plus a per-gigabyte data charge. The total monthly cost C (in dollars) is given by the formula C = 25 + 8d, where d is the number of gigabytes of data used. Construct a table showing the total monthly cost for d = 0, 2, 4, 6, 8, 10 gigabytes. Use your table to determine the increase in total cost when data usage increases from 4 gigabytes to 8 gigabytes.