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3 years ago

Factorise: 2x² -7x -4

2 answers:

5 0

The terms in x must be 2x and x. The factors of -4 are either -4 and 1, -1 and 4, -2 and 2 or 2 and -2. Trying each of the combinations we get (2x + 1)(x - 4) as the solution.

CaHeK987 [17]3 years ago

4 0

2x-7x-4x=0.875 the answer is 0.875 cause of the fact that seven and two are the ones with the varible

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Question 1,2, and 3 how do i factor those? Can you show the work and explain how?

DiKsa [7]

1: $3n^{2}+9n+6$

notice that each part is divisible by 3

$3n^{2}$ ÷ 3 = $n^{2}$

9n ÷ 3 = 3n

6 ÷ 3 = 2

so it becomes $3(n^{2} +3n+2)$

3n can be rewritten as 2n+n

-you want to rewrite it into two numbers that multiply to the number that's alone (in this case 2)

which would get you

$3(n^{2} +2n+n+2)$

Now that it's rewritten, you can factor out n + 2 from the equation.

the answer is

3(n+2)(n+1)

And you can check that by multiplying (n+2)(n+1) which is $n^{2} +2n+n+2$ and then each of those by 3, which is $3n^{2} +6n+3n+6$ or $3n^{2}+9n+6$ , our origional equation

2: $28+x^{2} -11x$

So I rewrote this as $x^{2} -11x+28$ (it's the same thing, just reordered using the commutative property)

now -11x can be rewritten as -4x-7x

(remember, the two numbers should multiply to equal 28, which is our constant.)

$x^{2} -4x-7x+28$

now we can factor out x from the first expression and -7 from the second

$x(x-4)-7(x-4)$

and lastly you factor out x-4,

which would give you

(x-4)(x-7)

Make sure to check your work and make sure it multiplies to $x^{2} -11x+28$

3: $9x^{2} -12x+4$

The first thing I notice when looking at this problem is that both 9 and 4 are perfect squares. Not only that, but they are the squares of 2 and 3, which are products of -12

So if you rewrite 9 as $3^{2}$ and 4 as $2^{2}$ , the equation becomes

$3^{2} x^{2} -12x+2^{2}$

now that $3^{2} x^{2}$ is ugly so it can be turned into $(3x)^{2}$

and -12x can be rewritten as $-2*3x*2$

so our equation now looks like $(3x)^2-2*3x*2+2^{2}$

There's a rule that says $a^{2} -2ab+b^{2} = (a-b)^{2}$

In our case, a=3x and b=2

so the final answer is

$(3x-2)^2$

5 0

2 years ago

What are the Horizontal and vertical shift of y = x+2-3

Nana76 [90]

If the equation is y=(x+2)-3 then the shifts are
3 down and 2 to the left

7 0

2 years ago

X 2 + y 2 - 10x - 8y + 1 = 0

Inessa [10]

Center: (5,4)

Radius: 2√10

Hope this helped☺☺

7 0

3 years ago

Solve the problem. Susan purchased some municipal bonds yielding 7% annually and some certificates of deposit yielding 9% annual

romanna [79]

The equations would be

Value: b + c = 19000
Interest: 0.07b + 0.09c = 1590

0.07b + 0.09 (19,000 - b) = 1,590
0.07b + 1,710 - .09b = 1,590
120 = .02b

B = 6,000
C = 13,000

So the correct answer is d. $6000 in bonds; $13,000 in certificates of deposit.

Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help.

6 0

3 years ago

Plzzzzz help i'm in desprate need of help with this

Ainat [17]

Answer:

Obtuse

Step-by-step explanation:

Right = has angle measure of 90°

Acute = has angle measure less than 90°

Equilateral = 2 or more angles whose angle measures are congruent to others

Circle = measures 360°

Obtuse = Angle measure greater than 90° and less than 180°

Hope this helps!

5 0

3 years ago