solve
7x+5(-3x-4)=-21-7x
7x+(-15x-20=-7x-21
-8x-20=-7x-21
7 7
-8x-20+7x=-21
-1x-20=-21
20 20
-1x/-1 = -1/-1
x=1
ok, but I am puzzled by your lines such as
7 7 and
20 20
When you show solutions to equations each new line should contain an equal sign separating the left side from the right side.
Inserting such lines as you have interrupts the "flow" of equations from one to the other.
In my class you would have lost a mark for "bad form".
To solve the equation: 7x + 5(-3x - 4) = -21 - 7x
You can start by applying the distributive property to simplify the equation:
7x + 5(-3x) + 5(-4) = -21 - 7x
Next, simplify further:
7x - 15x - 20 = -21 - 7x
Combine like terms:
-8x - 20 = -21 - 7x
To isolate the variable x, you need to get rid of the -7x term. You can achieve this by adding 7x to both sides of the equation:
-8x - 20 + 7x = -21 + 7x
Simplify:
-8x + 7x - 20 = -21 + 7x
Combine like terms:
-x - 20 = -21 + 7x
Next, you can get rid of the constant term on the right side of the equation by adding 21 to both sides:
-x - 20 + 21 = -21 + 21 + 7x
Simplify:
-x + 1 = 7x
To isolate x, you can subtract 7x from both sides of the equation:
-x + 1 - 7x = 7x - 7x
Simplify:
-8x + 1 = 0
To isolate x, you can subtract 1 from both sides of the equation:
-8x + 1 - 1 = 0 - 1
Simplify:
-8x = -1
Finally, to solve for x, you can divide both sides of the equation by -8:
(-8x) / -8 = (-1) / -8
Simplify:
x = 1
Therefore, the solution to the equation is x = 1.