I need help please thanks

What signals you that factoring by grouping is the best method to use when factoring a problem?

Write the fraction or mixed number and the decimal shown by the model

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.