Tomas is thinking of a number. If he doubles his number and subtracts 27, the result is 407. Of what number is Tomas thinking?

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Ahiker stands at an unknown elevation before he ascends 2 miles up a mountain to an elevation of 9 miles. find the elevation of the hiker before his ascent.

Ade and abc are similar. which best explains why the slope of the line between points a and d is the same as the slope between points a and b?