Find the value of c that makes the expression a perfect square trinomial. x2 − 19x + c A) 361 B) 38 C) 361 2 D) 361 4

A (361)

Step-by-step explanation:

A "perfect square trinomial" has the form

ax^2 + 2ab + b^2.  If a happens to be 1, which it is in the given x^2 − 19x + c, then 2(1)(b) = - 19.  Solving for b, we get b = -19/2.

Then b^2 in the general "perfect square trinomial" is the same as c:  (-19/2)^2, or 90.25, or 90 1/4, or 361/4/

Choosing A (361) makes the given expression a perfect square trinomial.

i assume that by 5 you mean 5 gallons.

(20)(0.25) = 15

removing 15 gallons reduces the tank from 20 to 5.