Math  /  Algebra

QuestionSolve by factoring: 2x22x=9x32 x^{2}-2 x=-9 x-3
Give either of the two solutions. x=x=

Studdy Solution

STEP 1

What is this asking? We need to find a value of xx that makes this equation true, by first rearranging the equation so it equals zero, and then factoring. Watch out! Don't forget to rearrange the equation to equal zero *before* factoring.
Also, remember there might be more than one solution!

STEP 2

1. Rearrange the equation
2. Factor the quadratic
3. Solve for xx

STEP 3

First, we need to **rearrange** our equation to make it equal to zero.
We can do this by adding 9x9x and 33 to both sides of the equation: 2x22x+9x+3=9x3+9x+32x^2 - 2x + 9x + 3 = -9x - 3 + 9x + 3 This simplifies to: 2x2+7x+3=02x^2 + 7x + 3 = 0 Now we have a **quadratic equation** set equal to zero, which is exactly what we need to start factoring!

STEP 4

We're looking for two numbers that multiply to 23=62 \cdot 3 = \textbf{6} and add up to 7\textbf{7}.
Think about it... what two numbers multiply to **6** and add to **7**?
It's 66 and 11!

STEP 5

Now we **rewrite** the middle term (7x7x) using these two numbers: 2x2+6x+1x+3=02x^2 + 6x + 1x + 3 = 0 See how 6x+1x6x + 1x is the same as 7x7x?
We're just rewriting it in a clever way to help us factor.

STEP 6

Now, we can **factor by grouping**: 2x(x+3)+1(x+3)=02x(x + 3) + 1(x + 3) = 0 Notice that (x+3)(x + 3) is a **common factor**!

STEP 7

So, we **factor it out**: (2x+1)(x+3)=0(2x + 1)(x + 3) = 0 Boom! We've factored our quadratic!

STEP 8

Now, we know that if two things multiplied together equal zero, then at least one of them *must* be zero.
So, we set each factor equal to zero: 2x+1=02x + 1 = 0 x+3=0x + 3 = 0

STEP 9

To solve 2x+1=02x + 1 = 0, we subtract 11 from both sides: 2x+11=012x + 1 - 1 = 0 - 1 2x=12x = -1Then, we divide both sides by 22: 2x2=12\frac{2x}{2} = \frac{-1}{2} x=12x = -\frac{1}{2}

STEP 10

To solve x+3=0x + 3 = 0, we subtract 33 from both sides: x+33=03x + 3 - 3 = 0 - 3 x=3x = -3

STEP 11

We found two solutions: x=12x = -\frac{1}{2} and x=3x = -3.
The problem asked for either solution, so x=3x = -3 is a perfectly valid answer!

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