2006-11-15 04:27:08 · 8 answers · asked by martha l 1 in Science & Mathematics ➔ Mathematics
This might Help
2006-11-15 04:31:47 · answer #1 · answered by Tara 5 · 0⤊ 0⤋
First rewrite as 7x - 3(x) -3(4) = 5x -21 as you multiple -3 times (x+4)
Next 7x -3x -12 = 5x -21 Be careful, the -3 part makes everything in parentheses negative.
7x-3x= 4x
4x-12 = 5x -21 now add 21 to both sides to get the largest x value by itself
4x + 9 = 5x Now subtract 4x from each side to solve for x
9 = x
Now plug back into original to see if it is correct.
7(9) - 3(9+4) = 5(9) -21
63 - 39 = 45 -21
24 = 24 thus x= 9 is correct.
2006-11-15 12:37:53 · answer #2 · answered by ciza29 3 · 0⤊ 0⤋
7x - 3(x + 4) = 5x - 21 distribute 3
7x-3x-12=5x-21 combine like terms
4x-12=5x-21 subtract 4x from each side
-12=x-21 add 21 to each side
9=x or
x=9
2006-11-15 12:46:56 · answer #3 · answered by yupchagee 7 · 0⤊ 0⤋
Distributive property
7x- 3x-12=5x-21
4x-12=5x-21
9=x
7(9)-3(9+4)=5(9)-21
63-39=45-21
24=24
2006-11-15 12:32:37 · answer #4 · answered by math_teacher_02 2 · 0⤊ 0⤋
7x - 3x - 12 = 5x - 21
7x - 3x - 5x = -21 +12
-x = -9
x = 9
2006-11-15 12:52:59 · answer #5 · answered by rose 1 · 0⤊ 0⤋
7x - 3(x+4) = 5x - 21
7x - 3x + 12 = 5x - 21
4x + 12 = 5x -21
then combine like terms
x = 33
2006-11-15 12:38:36 · answer #6 · answered by lil shay 2 · 0⤊ 0⤋
7x-3(x+4)=5x-21
7x-3x-12=5x-21
7x-3x-5x=-21+12
-1x=-9
x=-9/-1
x=9
2006-11-15 12:49:51 · answer #7 · answered by Saphira 3 · 0⤊ 0⤋
I agree with the math teacher
2006-11-15 12:35:07 · answer #8 · answered by Chrissy 5 · 0⤊ 0⤋