want to know if this right simplify and show all work

Question

-3x^2+4xy+7y^2+2(-3x^2+5xy+11y^2)
-3x^2+4xy+7y^2-6y^2+10xy+22y^2
-3x^2+14xy+45y^2
and
-6a-4a-2(100^2+3a)
-6a-4a^2+200+3a
3a-4a^2+200

Answer 1

in the second line of your solution, 2*(-3x^2) = -6x^2 not 6y^2. thus,
-3x^2 + 4xy + 7y^2 - 6x^2 + 10xy + 22y^2
-9x^2 + 14xy + 29y^2

..for the second problem, i think there are typos. please check the problem again. also, 100^2 is not equal to 200.