The minimum value of 2x+1 is 13

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

Which expression is equivalent to sq-80

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'