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7 votes
7 votes
For what is values of x does 4(3x-2) = 12x - 5? select all that apply.

A.12
B.-8
C.3
D.-3
E.none of these​

User Stefan Mohr
by
2.3k points

2 Answers

18 votes
18 votes

Answer:

‼️A) 12‼️

Explanation:

Key skills needed: Interior Angle Measure Theorem, Equation Creation

Step 1) First, we need to classify this shape. It has 7 sides, which means that we can use the Interior angle Theorem to find out the sum of all the interior angle measures

The theorem is: S = (n - 2)180S=(n−2)180

S is the sum of all interior angle measures

n is the number of sides of the polygon

Step 2) With this, we can plug in 7 for "n" (Since the figure has 7 sides) and get:

---> S = (7-2)180S=(7−2)180

---> (7-2) is 5 since 7 - 2 = 5 so --> S = 5(180)S=5(180)

---> 5(180) is the same as 5 x 180 which is 900 so --> S = 900S=900

This means that the sum of all interior angles is 900 degrees.

Step 3) Now, we have to find out the sum of all the angles that they gave us so:

---> 10x + 10x + 9 + 133 + 9x + 14 + 12x - 9 + 10x + 5 + 136 = 90010x+10x+9+133+9x+14+12x−9+10x+5+136=900

The left side is the sum of all interior angles in the shape, and the right side is what the sum should be when expressed as a number.

Step 4) We have to combine all like terms on the left side:

---> 10x + 10x + 9x + 12x + 10x = 51x10x+10x+9x+12x+10x=51x

---> 9 + 133 + 14 -9+5+136 = 2889+133+14−9+5+136=288

Step 5) This means that ---> 51x + 288 = 90051x+288=900

Subtract 288 from both sides and get:

---> 51x = 61251x=612 (900-288 = 612)

Then divide by 51 from both sides and get:

---> x = 12x=12 (612 ÷ 51 = 12)

Therefore A) 12 is your answer.

User Victor Welling
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3.5k points
14 votes
14 votes

I think it should be none of these.

The term on the left has to be even no matter what value of x and the right has to be odd no matter what value of x. Therefore, there shouldn't be an integer value of x that satisfies the equation, let alone the answer choices A-D.

User Silverburgh
by
3.1k points