Can someone explain how to do these problem and the formula

For the first one, you would have to subtract 5 from 8 which would give you x=3!! that is your answer. For the second one, you would have to subtract 3 from -6 which would give you -a=-9, but were not done here yet, we are going to multiply this by -1 because you can't have a negative variable which will give you a=9. And last but not least, on the third one, you would have to subtract 21 from 30 which will give you c=9. There is no specific formula to do these problems other than to get rid of the "third wheel number".

answer: need picture of problem

step-by-step explanation:

so a parallelogram is just like a square base times height. multiply 40 and 39 to get 1560 inches.

a triangle is base times height divided by two. so multiply 7.9 and 5 and then divide it by 2 to get 19.75inches.

the kite can be split into two separate triangles and added together to get the total area. 30 x 4 /2 which equals 60. make sure to double it for the two triangles making 120.