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Geometry!! help “B is between A and C. if AB = 3x -1. BC = x+3, and AC = 18. WHAT IS AB???

Geometry!! help “B is between A and C. if AB = 3x -1. BC = x+3, and AC = 18. WHAT-example-1
User Kamgman
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2 Answers

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Answer:

AB = 11

Explanation:

Given:

AB = 3x-1; BC = x+3; AC = 18

Since, AB and BC are parts of AC, we can conclude that AC is the sum of AB and BC.

Therefore, we have the following as an equation:

AB + BC = AC

Substitute each values;

(3x-1) + (x+3) = 18

Then solve for x;

(3x-1) + (x+3) = 18

4x + 2 = 18 //Combine like terms; 3x + x = 4x; 3 + (-1) = 2

4x = 18 - 2 //Since we want to solve the x, we want to let it alone, that's why we move the 2 to the other side (moving an expression past an equal changes its sign)

4x = 16

4x/4 = 16/4 //Divide both by four

x = 4

Now, substitute the x;

AB = 3x-1

AB = 3(4)-1

AB = 11

If you substitute the value of x such as four here;

(3x-1) + (x+3) = 18

(3(4)-1) + (4+3) = 18

11 + 7 = 18

18 = 18 //Checking

User Matchdav
by
8.2k points
5 votes

Answer:

C. 11.

Explanation:

AB + BC = AC

3x -1 + x + 3 = 18

4x = 1 - 3 + 18

4x = 16

x = 4

So, AB = 3(4) - 1

= 11.

User Gui Moura
by
8.9k points

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