2b - a = 5
Solve for a

What is the perimeter of trapezoid jklm? + units 2 + + units 9 + units 9 + + units

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).