3<6c+13<5 (Enter your answer in INTERVAL notation, using U to indicate a union of intervals; or enter DNE if no solution exists)

  (-5/3, -4/3)

Step-by-step explanation:

  3 < 6c +13 < 5 . . . . given

  -10 < 6c < -8 . . . . . subtract 13

  -10/6 < c < -8/6 . . . divide by 6

We can express the interval using reduced fractions as ...

  (-5/3, -4/3)

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

i dont know it

step-by-step explanation: