Which of the following situations best completes the following statement: When subtracting an integer is the same as .

multiplying its opposite
subtracting its opposite
adding its opposite
dividing its opposite

Given: △abc, ab=15, bd=9 ad ⊥ bc , m∠c=30°. find: the perimeter of the triangle.

Initially 100 milligrams of a radioactive substance was present. after 6 hours the mass had decreased by 4%. if the rate of decay is proportional to the amount of the substance present at time t, find the amount remaining after 24 hours. (round your answer to one decimal place.)

30 in the diagram line e and made parallel to each other and line p and q are transversal. use properties of special angles formed by parallel lines and their transversals to find the missing angle measures. m< 3=65 m< 15=120 m< 7= m< 4= m< 6= m< 1= m< 16= m< 18= m< 21= m< 10= m< 11= m< 12=