It is known that the values of formula 2A + 7 and 1-A are opposite to each other. Solve the equation 4-2a = 3x-1 about X

The values of 2A + 7 and 1-A are opposite to each other
So 2A + 7 + 1-A = 0
A = - 8
Substituting 4-2a = 3x-1
The solution is x = 7

It is known that ab = AC in the triangle as shown in the figure, arc with a as the center, respectively intersect the extension lines ab of Ca at e, f connect EF and extend the intersection BC at g. it is proved that EG is perpendicular to BC

It is proved that: ∵ e, f are arc drawn with a as the center and Ca extension line, the intersection point of ab ∵ AE = AF ∵ AEF = ∵ AFE (= ∵ BFG vs. vertex angle) ∵ AB = AC ∵ B = ∵ C ∵ AEF + ∵ C = ∵ BFG + ∵ B ∵ FGB =

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