Pleassee will give brainliest and lots of points in the attachments do the same thing for both, find the error and fix it.

a) the error is the first line, the angle isn't given as 90 degrees, but since the angles are bisected ,  they need to equal each other:

x-5 = 2x-6

add 6 to each side:

x+1 = 2x

subtract 1x from each side:

x = 1

2nd Picture:

Distance formula id subtracting X1 from X2 and Y1 from Y2, not X-y as shown.

d = √((-1 - 5)^2 + (15-16)^2)

d = √(-6^2 + -1^2)

d =√(36 +1)

d = √37 = 6.1

Bisect means to divide into 2 equal sections (not that their sum equals 90)

x - 5 = 2x - 6

   -5 = x - 6     subtracted "x" from both sides

    1 = x            added 6 to both sides

d = √[(x₂ - x₁)² + (y₂ - y₁)²]                  (not:√[ (x₁ - y₁)² + (x₂ - y₂)²])

  = √[(5 - (-1))² + (16 - 15)²]

  = √(6² + 1²)

  = √(36 + 1)

  = √37

  ≈ 6.1

sorry i dont know my friend

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.