Answer:
The answer is she sold 20 labradorite crytals and 3 galena crystals.
Step-by-step explanation:
First you times 20 x 20 and get 400 and then times 13 x 3 and get 39 and 400 plus 39 equals $439.
Let x be the number of weeks; therefore, the two linear equations are

Where T stands for the punches on the tea punch card and C for the punches on the coffee punch card.
Solving by substitution. Set T=C, then

Thus, substitute the value of x=3 into the first equation,

Thus, after 3 weeks, Josiah will have the same number of punches on each card, and he will have 23 punches on each card.
Answer:

Step-by-step explanation:
Connect points I and K, K and M, M and I.
1. Find the area of triangles IJK, KLM and MNI:

2. Note that

3. The area of hexagon IJKLMN is the sum of the area of all triangles:

Another way to solve is to find the area of triangle KIM be Heorn's fomula, where all sides KI, KM and IM can be calculated using cosine theorem.
Answer:
48.3
Step-by-step explanation:
Opposite sides are equal and parallel.
Diagonals bisect each other.
Sum of any two adjacent angles is 180°
Opposite angles are equal