Simpliftly(-8.)( -2)

how do i simplify it

Tina practice piano for 15 hours last month and 45 hours this month use multiplication to write a statement comparing me i was tina practice during the two months use addition to write a statement comparing the hours tina practice during the two months

What is the solution to the system of the equations? x = y - 3 x + 3y = 13

What number should be added to both sides of the equation to complete this square? x^2-10x=7