need help thanks

V. PROBLEM SOLVING. Read and analyze the given problem. Show your complete solution on the space provided. (4 items, 37 points) 9. Arianne and Roby Jane wishes to have Pip 840,000 in 5 years. If they can earn 8%, how much do they need to invest? What is the simple discount? 10. Find the compound interest and compound amount on the principal Php 250,500 that Adrian borrowed at 7.5% compounded semi annually for 3 years. 11. Find the value of x: a. 9x = 21 (mod30) b. 17x = 3 (mod 29) 12. Show that the set of all non-zero rational numbers with respect to the operation addition is a group. (8 points)