Hi pls help me with this. I don't get it since our prof didn't discuss it. I think it's part of optimal solution.

Pls show complete solution. Thank you!

Instruction:

Box the final answer and pls not handwritten. Type it. Thank you. ?

FINALS-ACTIVITY 3 Solve each system by substitution method. Check each solution. No need to graph. 1. y = 3x 2x+ y = 15 2. 3x - 2y = 11 y = 3 +2x 3. 2x - y = 14 . Submit your activity as a PDF file. . File name: FINALS.ACTIVITY.3.(LAST NAME.FIRST 3x - 7y = 10 . NAME.SECTION) Example: FINALS.ACTIVITY.3.CORPUZ.JAN.BSED MATH 24/ 24 00:00 / 00:01