Help me pls this is hard

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30 ∘c on monday, but decreased at a constant rate in the next 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.