Anonymous
Anonymous asked in Science & MathematicsMathematics · 9 years ago

The value of x in 3x + 4 = -10 is what? explain the formula please

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To generalize solving for x, or any variable really, all you have to do is get x, or any given variable, on one side of the equation all by itself. You want to remember order operations to make it easier. We normally do it in reverse when solving for a variable. Add and subtract before you multiply and divide usually.

3x+4=-10

first step is subtracting 4 from each side to get rid of the plus 4 on the left. To keep an equation equal you have to do the same thing to both sides for instance

1=1 is true, if we add 4 to each side we get

5=5 which is true

if we only add 4 to one side we get

5=1 which is not true. Same thing applies when dealing with a variable such as x.

so back to where we were

subtract 4 from each side

(3x+4)-4=(-10)-4

3x=-14

now divide both sides by three to get just x.

(3x)/3=(-14)/3

x= -14/3

• There isn't really a formula but I'll try and go step by step:

3x + 4 = -10 (subtract 4 from -10)

-4. -4

3x = -14 (you want 3x alone, now divide)

3. 3

x = - 4.6666667

(3x is just 3 times x, so when moving the number to the other side do the opposite, it's hard to explain - when there was 3x + 4 = -10 to get 3 alone you have to subtract 4 from -10, if "4" happened to be "-4" instead in this equation you would add 4 to -10)

My explanation wasn't extremely detailed but I hoped it helped a bit. I had an A+ throughout Algebra in school.

• To solve a problem like this, you need to isolate the variable ( the letter x). First thing to do is move the +4 to the opposite side of the equal sign. To do this, turn the +4 into a -4. This will cancel it from the left side of the equation. Now take complete -10-4=? To get an answer for the right side. You still need to get the x by itself so that means dividing by 3 since 3x means 3 times x. When you divide 3x by 3 you cancel out the 3 and are just left with x. Now take your answer from -10-4 and divide it by 3. The answer you get is what x represents. Check your answer by going back to the main problem and changing x into your answer. If it equals -10 then it's correct. Example: 2x+5=-3, subtract 5 from both sides to get 2x=-8, divide 2 to get x=-4. Check: 2(-4)+5 equals -3 so the answer is correct.

• First if all, you need to get X on it's own.

Step 1) take the positive 4 to the other side: 3X = -10 + 4

Step 2) 3X = -14

Step 3) Divide both sides by 3 to get X on it's own

Step 4) 3X / 3 = -14 / 3

Step 5) The 3's on the left would cancel each other out to become: X = -14 / 3

Step 6) Good luck with the rest

• First subtract 4 from both sides of equal sign.

3x+4 - 4 = -10 - 4

which is in turn,

3X = -14

now divide both sides by 3, Which will be equal to:

3x/3 = -14/3

x = -14/3

Source(s): school algebra text book.
• HI

basically you just subtract 4 from each side getting

3x = -14

then you divide by 3 on each side

x = -14/3

that is the answer. I hope it helped