The problem states that $m\angle 11 = x - 4$ and $m\angle 12 = 2x - 5$. We are given a diagram where $\angle 11$ and $\angle 12$ form a linear pair (they are supplementary). We need to find the value of $x$.

GeometryAnglesLinear PairSupplementary AnglesAlgebra
2025/4/1

1. Problem Description

The problem states that m11=x4m\angle 11 = x - 4 and m12=2x5m\angle 12 = 2x - 5. We are given a diagram where 11\angle 11 and 12\angle 12 form a linear pair (they are supplementary). We need to find the value of xx.

2. Solution Steps

Since 11\angle 11 and 12\angle 12 form a linear pair, their measures add up to 180180^\circ.
m11+m12=180m\angle 11 + m\angle 12 = 180
Substitute the given expressions for the measures of the angles:
(x4)+(2x5)=180(x - 4) + (2x - 5) = 180
Combine like terms:
3x9=1803x - 9 = 180
Add 9 to both sides of the equation:
3x=1893x = 189
Divide both sides by 3:
x=1893x = \frac{189}{3}
x=63x = 63

3. Final Answer

x=63x = 63

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