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3 years ago

Solve for x...........................

Mathematics

1 answer:

yaroslaw [1]3 years ago

5 0

Answer:

Option A is correct, i.e. x = -3, x = 7.

Step-by-step explanation:

Given the equation is x² -4x -21 = 0.

We can compare it with general quadratic equation i.e. ax² +bx +c =0.

then a = 1, b = -4, c = -21.

We can use Quadratic formula as follows:-

x = ( -b ± √(b²-4ac) )/2a

x = ( +4 ± √(16-4*1*-21) )/2*1

x = ( +4 ± √(16+84) )/2

x = ( +4 ± √(100) )/2

x = ( +4 ± 10 )/2

x = (4+10)/2 or x = (4-10)/2

x = 14/2 or x = -6/2

x = 7 or x = -3

Hence, option A is correct, i.e. x = -3, x = 7.

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I need help with number 2 don’t understand it. someone help plz.

Sholpan [36]

I would say solve each diameter equation and order them fromleast to greatest, for example

1 Venus- 7.52×10 to the power of 3
So first simplify 10 to the power of 3 which is, 1000. Then you multiply 7.52 by 1000 which gets you 7520.

So solve each equation and order it

8 0

3 years ago

Read 2 more answers

The domain of both

Margarita [4]

Answer:

The domain of function $h(x)$ is set of all real numbers.

Domain: (-∞,∞)

Step-by-step explanation:

Given:

$f(x)=x-6$

$g(x)=x+6$

the domain of both the above functions is all real number.

To find domain of :

$h(x)=f(x)g(x)$

Substituting functions $f(x)$ and $g(x)$ to find $h(x)$

$h(x)=(x-6)(x+6)$

The product can be written as difference of squares. $[a^2-b^2=(a+b)(a-b)]$

∴ $h(x)=x^2-36$

The degree of the function $h(x)$ is 2 as the exponent of leading term $x^2$ is 2. Thus its a quadratic equation.

For any quadratic equation the domain is set of all real numbers.

So Domain of $h(x)$ is (-∞,∞)

7 0

4 years ago

Evaluate 4a + 7b + 3a − 2b for a = 5 and b = −3.

blsea [12.9K]

Answer:

Step-by-step explanation:

$4a+7b+3a-2b\qquad\text{combine like terms}\\\\=(4a+3a)+(7b-2b)\\\\=7a+5b\qquad\text{put a = 5 and b = -3 to the expression}\\\\7(5)+5(-3)=35-15=20$

5 0

4 years ago

WhT is this rounded to the nearest hundredth

Sergio [31]

Answer:

32.02

Step-by-step explanation:

The number that is in the hundredths place is five. You can remember this by knowing that the decimal point counts as one and all the number to the right of the decimal point count as zero. So 0 is in the tenths place, 1 is in the hundredths place, 5 is in the thousandths place, 6 is in the ten thousandths place and so on. So if you round this number to the nearest hundredth, you'll get 32.02 because if you're rounding a number and the number you're rounding with (knowing that the number you're rounding will always be rounded with the number to the right of it) is 5 or greater than 5, that number that you have to round will go up one unit.

I hope this helped!

3 0

3 years ago

Given that the expression x³_ ax² + bx+c leaves the same remainder when divided by x + 1 or x-2, find 'a' in terms of 'b'.

goblinko [34]

Answer:

Hi,

a=b+3

Step-by-step explanation:

$\begin{array}{c||c|c|c|c}&x^3&x^2&x&1\\---&---&---&---&---\\&1&-a&b&c\\x=-1&&-1&a+1&-a-b-1\\---&---&---&---&---\\&1&-a-1&a+b+1&c-a-b-1\\\end{array}$

$\begin{array}{c||c|c|c|c}&x^3&x^2&x&1\\---&---&---&---&---\\&1&-a&b&c\\x=2&&2&4-2a&2b+8-4a\\---&---&---&---&---\\&1&2-a&b+4-2a&c+2b+8-4a\\\end{array}$

Thus:

c+2b+8-4a=c-a-b-1

3b-3a=-9

5 0

2 years ago