How many solutions 2a + 4 = a + a + 4

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Long division the problem is 40 ➗ 348 = ?

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?