Please help! This is a big part of my grade. I will give brainliest.

Which statement is always true? a. square bcdf is a rectangle. b. rectangle gjkm is a square. c. quadrilateral stpr is a trapezoid. d. parallelogram abcd is a rhombus.

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab