Answer:
-14x +21 = 7x -24
Explanation:
We assume your use of the multiplication symbol in this problem (×) is intended to represent the variable x.
The distributive property tells you that the factor outside parentheses multiplies each of the terms inside parentheses:
a(b+c) = ab+ac
Your equation can be simplified as ...
-7(2x -4) -7 = 3(x -5) +4x -9 . . . . given
-7(2x) +(-7)(-4) -7 = 3x +3(-5) +4x -9 . . . . use the distributive property
-14x +28 -7 = 3x -15 +4x -9 . . . . . . . . . . . carry out the multiplication
-14x +21 = x(3+4) -(15 +9) . . . . identify and group like terms on the right*
-14x +21 = 7x -24 . . . . . . . . . . do the arithmetic
_____
* note that the distributive property can also be used to combine terms:
3x +4x = x(3+4) = 7x