Answer:

Step-by-step explanation:
refer to solution in the picture
A= bh divide by 2 so you'll multiply 10x8 the product would be 80 and so you divide 80 by 2 and get 40 as your result.
13 factored out is 13x - 39 add 39 to both sides it equals 13x=78 and 78 divided by 13 is 6 the anwser is x=6
16 because 5 times 4 = 20 there for you multiply 4 times 4 to get 16
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