HELP ME PLEASE. i really need it asap

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

What three-dimensional solid have 6 rectangular faces, 2 equal bases that are not rectangles and 18 edges

The value of x in this system of equations is 1. 3x + y = 9 y = –4x + 10 substitute the value of y in the first equation: combine like terms: apply the subtraction property of equality: apply the division property of equality: 3x + (–4x + 10) = 9 –x + 10 = 9 –x = –1 x = 1 what is the value of y?