Did you make a sketch? That'd be your best friend to express the double integral sum as a single one.
In evaluating a double integral over a region , a sum of iterated integrals was obtained as follows:
Sketch the region and express the double integral as an iterated integral with reversed order of integration.
Find a, b, g1(x), and g2(x).
I said a was 0 b was 7, g1(x) was 7 and g2(x) 0
but thats not correct so what next?