Help me understand this and what is right Brainliest.

the first one

Step-by-step explanation:

Think of it this way. If it needs to be greater than -11, that means there is some kind of restraint. that would be in this situation, its under a square root. if you plug in -11, it should equal 0, so it has to be x+11 under square root. The second one wouldn't work since that would make it square root of -22 and thats imaginary, same thing with all the others, when you plug in -11, the last 3 would come negative. the first one is the only one that cancels the negative and gives you 0

4 and i cant help u understand it

Step-by-step explanation:

answer:   28.56 feet (approx)

step-by-step explanation:

since, triangle abc has measure of angle c equal to 55 degrees, measure of angle abc equal to 90 degrees, and length of bc equal to 20 feet.

we have to find out the measurement of segment ab.

therefore, tan 55° =

but bc = 20 feet.

⇒ tan 55 ° =  

⇒ ab = 20 × tan 55 °

⇒ ab = 20 × 1.42814800674

⇒ ab = 28.5629601348   ≈ 28.56 feet