8th term of the geometric sequence 10,-40,160

In the rectangle below ac=30 units what is de

Four congruent circular holes with a diameter of 2 in. were punches out of a piece of paper. what is the area of the paper that is left ? use 3.14 for pi

Solve the following simultaneous equation by using an algebraic method (either substitution or elimination) 2x + 3y=-4 4x-y=11