Remember yo can do anything to an equation as long as you do it to both sides
so
remember distributive property
a(b+c)=ab+ac
so first distribute
2(3x)+2(-9)=18x
6x-18=18x
minus 6x both sides
-18=12x
divide both sides by 12
-18/12=x
-9/6=x
-3/2=x
easier way is to first divide both sides by 2
x=-3/2
Part A you would just distribute your 3 to your X and your 5. After doing that you would get 3x+15+x=4x. Next you would combine like terms, meaning combine your x's together that is on the same side of your equal sign. So you would add 3x and x. When finished with that you would get, 4x+15=4x. You would then subtract your 4x on both sides of your equal sign. You then would get 15=0 which is no solution.
Part B you would distribute your 4 to your 1 and -x. After doing this your equation should then look like 4-4x=5x+8. Next you would try to get your like terms together. You would add 4x on both sides of your equal sign. Your equation should then look like 4=9x+8. Next you would subtract your 8 on both sides of the equal sign because your getting your terms together. Your equation should then look like, -4=9x. This answer would be one solution.
Part C you would combine your like terms, meaning add your 2x and x together to get your equation looking like, 3x+5=5+3x. You can tell just by looking at this equation it's going to be a infinite number of solutions.
Hope this helps! (:
4x=20
4/4x=20/4
x=5
u want to isolate the variable to solve these equations
Letter D because you need to multiply all the letters of the alfabet (36) and multiply 36 by 1000 and then divide the answer by 100 and you get the letter D