How do you evaluate $- ( 4x - 7) = 5x - ( 5x + 21)$ ?

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Answer 1 · 2017-09-14T10:30:46

See a solution process below:

First, remove all of the terms from parenthesis being careful to manage the signs of the individual terms correctly:

$-4x - (-7) = 5x - 5x - 21$

$-4x + 7 = 0 - 21$

$-4x + 7 = -21$

Next, subtract $color(red)(7)$ from each side of the equation to isolate the $x$ term while keeping the equation balanced:

$-4x + 7 - color(red)(7) = -21 - color(red)(7)$

$-4x + 0 = -28$

$-4x = -28$

Now, divide each side of the equation by $color(red)(-4)$ to solve for $x$ while keeping the equation balanced:

$(-4x)/color(red)(-4) = (-28)/color(red)(-4)$

$(color(red)(cancel(color(black)(-4)))x)/cancel(color(red)(-4)) = 7$

$x = 7$

How do you evaluate - ( 4x - 7) = 5x - ( 5x + 21)- ( 4x - 7) = 5x - ( 5x + 21)?