If 5+20*2^(2-3x)=10*2^(-2x)+5, what is the value of x? a –3 b –2 c 2 d 3

Step 1: get rid of the +5 on both sides.
Step 2: divide by 10 on both sides

Then you have: 2*2^(2-3x) = 2^(-2x)

The factor 2 on the left can be brought into the exponent because you're simply multiplying with 2 more...

2^(1+2-3x) = 2^(-2x)

Now you can equate the exponents:

3-3x = -2x => 3 = -2x+3x => x=3

so d is your answer.

No solution : there is no number of boxes that she bought