Can anybody help me please hurry this is due

Which value is not a solution of 8x^3 – 1 = 0

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15