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# When the sum of a number and -5 is multiplied by -7, the result us 49.

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-5[x+(-7)]=49 <----- I feel like my setup is wrong. I don't even understand how to solve it.

Feb 28, 2019

#1
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$$-5(x+(-7)]=49\\ -5x + 35 = 49\\ -5x = 14\\ x = -\dfrac{14}{5}$$

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Feb 28, 2019
#3
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-14/5 is 2.8 just btw so u don't get confused

DivideByZero  Feb 28, 2019
#4
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I think you mean -2.8.

tertre  Feb 28, 2019
#6
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yea i did sorry

DivideByZero  Feb 28, 2019
#2
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DON'T STRESS

Look, I know it looks hard, but just power through and take it step by step

-5(x+[-7])=49

Distribute

-5x+35=49

-35     -35

-5x=14

Divide

x=-2.8

-DBZ Feb 28, 2019
edited by DivideByZero  Feb 28, 2019
#5
+1

When the sum of a number and -5 is multiplied by -7, the result us 49.

How do you eat an elephant?  One bite at a time.

Take this problem apart and look at one bite at a time.

"When the sum of a number and –5 is..."       What does this mean?  First, there's a number.  We don't know what it is so let's let X stand for it. So the sum of X and –5 is simply X +(–5), or X–5.  Put some parentheses around that, like this: (X–5)

What is the next part of the problem?  "...is multiplied by –7"  so let's write out that multiplication: (X–5)(–7)

The problem says that that equals 49, so put it all together           (X–5)(–7) = 49

Then just multiply the left side and the equation looks like this:       –7X + 35 = 49

Subtract 35 from both sides                                                              –7X = 14

Divide both sides by –7                                                                         X = –2

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Feb 28, 2019
#7
+1

Sum of a number and -5    ====   (x+-5)

is multiplied by  -7        ======  7(x-5)

the result is 49      =========== -7(x-5) = 49    use distributive property

-7x + 35 = 49    subtract 35 from both sides of the equation

-  7x = 14        divide both sides by -7

x = -2

Feb 28, 2019
edited by ElectricPavlov  Feb 28, 2019
#8
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i think you accidentally multiplied by 7 instead of -7

DivideByZero  Feb 28, 2019
edited by DivideByZero  Feb 28, 2019
#9
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Step 1: Simplify both sides of the equation.

−5(x−7)=49

(−5)(x)+(−5)(−7)=49(Distribute)

−5x+35=49

Step 2: Subtract 35 from both sides.

−5x+35−35=49−35

−5x=14

Step 3: Divide both sides by -5.

$$\frac{-5x}{-5}=\frac{14}{-5}$$

x= -14/5

answer is x=-14/5 Feb 28, 2019
#10
0

Big Brother, where does the problem say to multiply anything by –5 ?

Feb 28, 2019