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C. 13 1/2 feet

Step-by-step explanation:

The problem states that a thresher shark is 3 times as long as a sandbar shark. A sandbar shark is 4 1/2 feet, so to solve, you would either multiply 4 1/2 by three OR, to utilize the bar model, you would add 4 1/2 plus 4 1/2 plus 4 1/2 which would equal 13 1/2. :)

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.