Find the measure of angle 1.

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  (a)  84°

Step-by-step explanation:

If the upper side of angle 1 is extended so that it crosses the lower parallel, the angle it makes there corresponds to the one marked 51°, so is also 51°. That makes angle 1 the exterior angle of a triangle with remote interior angles of 51° and 33°. Angle 1 is the sum of those angles:

  ∠1 = 51° +33° = 84°

Alternate solution

Draw a line through the vertex of angle 1 parallel to the other two parallel lines. The lower half of angle 1 is then an alternate interior angle to the one marked 33°, so is 33°. The upper half of angle 1 is a corresponding angle to the one marked 51°, so is 51°. That makes angle 1 be the sum of 33° and 51° angles, so 84°.

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x