In a parallelogram, opposite angles are congruent.
Since angles z and 124° are opposite angles in the parallelogram, they are congruent angles.
Therefore we have:
Answer:
Step-by-step explanation:

BC = 15 cm
3x = 15
x = 15/3 = 5
AB =4x = 4*5 = 20 cm
Pythagorean theorem,
AC² = AB² + BC²
= 20² + 15 ²
= 400 + 225
= 625
AC = √625 = 25 cm
AC = 25 cm

Answer:
-9x^3+4x^2+5
Step-by-step explanation:
(6x^2 - 3 - 5x^3) - (4x^3 +2x^2 - 8)
distribute the minus sign
(6x^2 - 3 - 5x^3) - 4x^3 -2x^2 + 8
Combine like terms
-5x^3 -4x^3 +6x^2 - 2x^2 -3 +8
-9x^3+4x^2+5
Simply plug in x = 4 in to the function
f(4) = 1/3 * 4
f(4) = 4/3