which best describes the system of equations?

3x = 5 − 4y
6x + 8y = 7

Aplot of land has been surveyed for a new housing development with borders ab, bc, dc, and da. the plot of land is a right trapezoid with a height of 60 feet and an opposite leg length of 65 feet

The pyramid shown has a square base that is 24 centimeters on each side. the slant height is 16 centimeters. what is the lateral surface area?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?