How do you know when a linear system has no solution.

The trigonometric ratios sine and secant are reciprocals of each other

Simplify. −4x^2 (5x^4−3x^2+x−2) −20x^6−12x^4+8x^3−8x^2 −20x^6+12x^4−4x^3+8x^2 −20x^8+12x^4−4x^2+8x −20x^6+12x^4+4x^3−8x^2

If you measured the width of a window in inches and then in feet with measurement would you have the greater number of units