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Bogdan [553]
3 years ago
15

Using the quadratic formula to solve 7x2 – x = 7, what are the values of x?

Mathematics
2 answers:
lesya692 [45]3 years ago
7 0

Answer:c

Step-by-step explanation:

Kruka [31]3 years ago
5 0
How the quadratic formula works:

For any quadratic equation ax² + bx + c = 0, the solution is x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}.

In the case of our equation 7x² - x = 7, first we need to subtract 7 from each side so that we have 0 on the right.
7x² - x - 7 = 0

Identify the values of a, b, and c.
a = 7, b = -1, and c = -7.

Plug these into our quadratic formula and solve.

x=\frac{-(-1)\pm\sqrt{(-1)^2-4(7)(-7)}}{2(7)}=\boxed{\frac{1\pm\sqrt{197}}{14}

There are two values for x: (1+√197)/14 and (1-√197)/14.
The approximate values for these are 1.073976 and -0.931119.
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3 years ago
The new pool cover is 35 feet long and 13 feet wide with the overhang.
earnstyle [38]

Answer:

455

Step-by-step explanation:

multiply the width by the length

3 0
3 years ago
6( 5-8x) +12= -54
UkoKoshka [18]
<span>6( 5-8x) +12= -54 
30-48x+12=-54 this comes from distributing(multiplying) 6x5 and 6 times -8x
30+12-48x=-54 you have to add the coefficients 30+12
42-48x=-54  
-42        -42 
-----------------------
-48x=-96 divide by -48
x=2</span>
5 0
3 years ago
Read 2 more answers
Solve the system by using a matrix equation (Picture provided)
Katyanochek1 [597]

Answer:

Option b is correct (8,13).

Step-by-step explanation:

7x - 4y = 4

10x - 6y =2

it can be represented in matrix form as\left[\begin{array}{cc}7&-4\\10&-6\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{c}4\\2\end{array}\right]

A= \left[\begin{array}{cc}7&-4\\10&-6\end{array}\right]

X= \left[\begin{array}{c}x\\y\end{array}\right]

B= \left[\begin{array}{c}4\\2\end{array}\right]

i.e, AX=B

or X= A⁻¹ B

A⁻¹ = 1/|A| * Adj A

determinant of A = |A|= (7*-6) - (-4*10)

                                    = (-42)-(-40)

                                    = (-42) + 40 = -2

so, |A| = -2

Adj A=  \left[\begin{array}{cc}-6&4\\-10&7\end{array}\right]

A⁻¹ =  \left[\begin{array}{cc}-6&4\\-10&7\end{array}\right]/ -2

A⁻¹ =  \left[\begin{array}{cc}3&-2\\5&-7/2\end{array}\right]

X= A⁻¹ B

X=  \left[\begin{array}{cc}3&-2\\5&-7/2\end{array}\right] *\left[\begin{array}{c}4\\2\end{array}\right]

X= \left[\begin{array}{c}(3*4) + (-2*2)\\(5*4) + (-7/2*2)\end{array}\right]

X= \left[\begin{array}{c}12-4\\20-7\end{array}\right]

X= \left[\begin{array}{c}8\\13\end{array}\right]

x= 8, y= 13

solution set= (8,13).

Option b is correct.

3 0
3 years ago
Shane set his watch 18 seconds behind, and it falls behind another 2 seconds every day. How many days has it been since Shane la
suter [353]

Answer:

14 days

Step-by-step explanation:

18 seconds on day 1

44-18=26

26/2=13 days

Day 1 +13 Additional days=14 days

7 0
3 years ago
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