Answer:if your still doing this comment and I will try helping
Step-by-step explanation:
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6(3+a)=18+6a
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First find the area of the rectangle by multiplying the length and width of the rectangle, so 12 x25=300. Then find the area of the triangle, which is length x height/ 2. So 8 x 25=200/2=100. Then add the two answers together to get 400.
