Amy had n dollars to begin with. She just spent 21 dollars. Using n, write an expression for the number of dollars she has left.

Consider symmetrically placed rectangular insulators with uniformly charged distributions of equal magnitude as shown. x y −−−−−− what is the direction of the net field at the origin?

A3cm×3cm\greend{3\,\text{cm} \times 3\,\text{cm}} 3cm×3cm start color greend, 3, space, c, m, times, 3, space, c, m, end color greend rectangle sits inside a circle with radius of 4cm\blued{4\,\text{cm}} 4cm start color blued, 4, space, c, m, end color blued . what is the area of the shaded region? round your final answer to the nearest hundredth.

Simplify each expression. use positive exponents. show work . (x –2 y –4 x 3 ) –2