20 is x = 1.6
To find this, first distribute 3 into (x-7), then combine like terms on that side of the equation. Then, add 2x to 3x to get 5x, setting the variables on one side of the equation. Once you do this, add 16 to both sides, leaving you with 5x = 8. Then divide 8 by 5 to get 1.6.
22 is x = 51
To get this, first multiply seven and five. This will cancel out that denominator and leave the numerator and variable free. Then, multiply the product (35) by 3 in order to get rid of all fractions in the equation. You should now be left with x + 1 + x + 2 = 105. Combine like terms to get 2x + 3 = 105. Now, subtract 3 from 105 and divide the answer by 2 to get 51.
24 is x = -3 plus or minus the square root of five all over 6.
You have to first make this into a standard equation, so you do this by adding 1 to both sides, giving you x squared + 3x + 1. Now, this can't be factored, so you need to do the quadratic equation. Since 5 doesn't have a square root, you're left with that answer.
Hope this helps!