Element X is a radioactive isotope such that every 26 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 680 grams, how much of
the element would remain after 19 years, to the nearest whole number?

Identify the translation rule on a coordinate plane that verifies that square a(-4, 3), b(-4, 8), c(-9, 3), d(-9, 8) and square a'(-3, 2), b'(-3, 7), c'(-8, 2), d'(-8, 7) are congruent.

The figure above shows the lengths of thesides of a rectangle in cm. find the valuesof x and y and then the area of the rectangle.sides: top= 3x - yleft= 3y + 4bottom= 2x + yright= 2x - 3 use both methods, elimination and substitution, if possible.

How do you use the elimination method for this question? explain, because i really want to understand!