What is the solution of equations?

y = 3x + 5
y = -x + 3

a. (2.1, 11.3)
b. (-2.1, 5.1)
c. (-0.5, 3.5)
d. (0.5, 2.5)

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

Three coins are flipped. what is the probability that there will be at least two tails?

If f(x) = 3x2 - 2x+4 and g(x) = 5x + 6x - 8, find (f-g)(x).