7 (2x + 5) = 56?

2008-03-03 12:06 pm
Would someone help me do this :( i did it once and got it wrong and now I dont know the right thing to do..

回答 (10)

2008-03-03 12:43 pm
✔ 最佳答案
Clearly, we're trying to find x here, and the way to do that would be by isolating off all the other numbers to one side, so that x is on it's own. Then, we can find the answer to 'x = ?'
Note: The square brackets below aren't necessary, and are only there to help distinguish between the sides of the equation.

First, start off by dividing both sides of the equation by 7.
[7(2x+5) / 7] = [56 / 7]
which equals to:
2x+5 = 8

Then you can remove 5 from each side.
[2x+5 - 5] = [8 - 5]
which equals to:
2x = 3

Finally, finding x is just one step away. Divides both sides by 2 to get x alone.
[2x / 2] = [3/2]
and....
x = 1.5

**If you're not sure of the answer's validity, just plug in '1.5 for x', and work the problem away. The answer should be 56.**

I hope you can use my to help you computer further algebraic equations.
參考: I was a high school student last year, and now I'm in college.
2008-03-04 12:59 am
2x + 5 = 8
2x = 3
x = 3 / 2
2008-03-03 8:11 pm
7(2x+5)=56
==> 2x+5=8
==> 2x=3
==> x=3/2
==> x=1.5
2008-03-06 11:06 am
7 (2x+5)=56

distributive property

7*2x= 14x+5=56
2008-03-03 10:43 pm
7(2x + 5) = 56
2x + 5 = 56/7
2x = 8 - 5
x = 3/2
x = 1 1/2 (1.5)
2008-03-03 8:15 pm
7(2x+ 5) = 56
14x + 35 = 56
14x = 21
x = 21/ 14 or 3/2
2008-03-03 8:15 pm
multiply 7 to 2x + 5..by distributive property of multiplication, we will get:

14x + 35 = 56 "transpose" 35
14x = 56-35
14x = 21 divide now both sides of the equation by 14..and we will get...

x = 3/2 or 1.5
2008-03-03 8:19 pm
7 (2x + 5) = 56
14 X + 35 = 56
14x = 21
x = 21/14
= 1.5
2008-03-03 8:13 pm
14x+35=56
-35 -35

14x=21
_14 _14

x=1.5
2008-03-03 8:11 pm
7 (2x + 5) = 56 (/7)
2x + 5 = 8 (-5)
2x = 3 (/2)
x = 1.5


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