So just use a calculator but here goes
3^1=3
3^2=9
3^3=27
3^4=81
3^5=243
3^6=729
and 3^7 is 2187 which is excluded
Here's how you do long division
Because ABCD is an isosceles trapezoid, the angles A and D are congruent.
BA and CD are congruent (given) and AD is congruent to itself (reflexive property).
Then triangles BAD and CDA form a pair of SAS triangles, so they are congruent.
BD and CA are corresponding parts in those triangles, so they are congruent (CPCTC).
I assume you are being asked to solve these equations. Since there wasn't an explanation as to how you are expected to solve them, I chose to demonstrate how to use a calculator matrix function. You can find matrix calculators online. My instructions are for a TI-84
Push the blue 2nd button then push x^-1 button (it says matrix above this button in blue)
Arrow over to edit to change the dimensions of the matrix and to put in your values. You have 3 equations (3 rows) and 4 terms (4 columns) so you put a 3x4 in for the dimension and the coefficients (see images).
You use the rref option in the math column in matrix to calculate the answer.
The numbers at the end are the solutions. x = -4, y = 2, z = -1
They both would need to get two toppings to cost the same amount which would be $8.60