How do you simplify $- 21 (a + 2 b) + 14 a - 9 b$ $-21(a+2b)+14a-9b$ ?

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Answer 1 · 2016-01-27T03:29:43

$- 7 a - 51 b$ $-7a-51b$

$- 21 (a + 2 b) + 14 a - 9 b$ $-21(a+2b)+14a-9b$

Distribute

$- 21 a - 42 b + 14 a - 9 b$ $-21a-42b+14a-9b$

Add like terms

$- 21 a + 14 a - 42 b - 9 b$ $-21a+14a-42b-9b$
$- 7 a - 51 b$ $-7a-51b$

:D

Answer 2 · 2016-01-27T03:32:42

$- (7 a + 51 b)$ $-(7a+51b)$

$- 21 (a + 2 b) + 14 a - 9 b$ $-21(a+2b)+14a-9b$

Mutliply $a$ $a$ and $b$ $b$ by $- 21$ $-21$ :
$- 21 a - 42 b + 14 a - 9 b$ $-21a - 42b + 14a - 9b$

Reorganize and operate:
$14 a - 21 a - 42 b - 9 b$ $14a-21a-42b-9b$

$- 7 a - 51 b$ $-7a-51b$

Optional, common factor $- 1$ $-1$ :
$- (7 a + 51 b)$ $-(7a+51b)$

How do you simplify −21(a+2b)+14a−9b-21(a+2b)+14a-9b?