Question

I really need this done please help me out ​

Answer 1

10)x = 9

11)x = 5

Explanation:

10) Sum of all three angles of a triangle is 180°.

13x + 2 + 3x - 4 + 5x -7 = 180

13x + 3x + 5x + 2 - 4 - 7 = 180

Combine like terms,

21x - 9 = 180

Add 9 to both sides,

21x = 180 + 9

21x = 189

Divide both sides 21,

x = 189 ÷ 21

`\boxed{\bf x = 9}`

Option D.

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11) Exterior angle property of triangle:

Exterior angle equals the sum of interior opposite angles (remote angles).

19x - 18 = 7x + 1 + 10x- 9

19x - 18 = 7x + 10x + 1 - 9

19x - 18 = 17x - 8

Add 18 to both sides,

19x = 17x - 8 + 18

19x = 17x + 10

Subtract 17x from both sides,

19x - 17x = 10

2x = 10

Divide both sides by 2,

x = 10 ÷ 2

`\boxed{\bf x = 5}`

Option B

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