All categories

3 years ago

Solve the equation by completing the square

Mathematics

1 answer:

Ilya [14]3 years ago

4 0

Answer:

We got the quadratic equation:

$x^2+8x-3=0$

Solving by completing the square:

$x^2+8x-3=0\\x^2+8x+16-16-3=0\\(x+4)^2-16-3=0\\(x+4)^2-19=0\\(x+4)^2=19\\x+4=\pm \sqrt{19} \\x=-4\pm \sqrt{19} \\\\x_{1} =-4+\sqrt{19} \\x_{2} =-4-\sqrt{19}$

Therefore, the answer is letter C

You might be interested in

Solve the following using Substitution method 2x – 5y = -13 3x + 4y = 15

Digiron [165]

$\huge \boxed{\mathfrak{Question} \downarrow}$

Solve the following using Substitution method

2x – 5y = -13

3x + 4y = 15

$\large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}$

$\left. \begin{array} { l } { 2 x - 5 y = - 13 } \\ { 3 x + 4 y = 15 } \end{array} \right.$

To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.

$2x-5y=-13, \: 3x+4y=15$

Choose one of the equations and solve it for x by isolating x on the left-hand side of the equal sign. I'm choosing the 1st equation for now.

$2x-5y=-13$

Add 5y to both sides of the equation.

$2x=5y-13$

Divide both sides by 2.

$x=\frac{1}{2}\left(5y-13\right) \\$

Multiply $\frac{1}{2}\\$ times 5y - 13.

$x=\frac{5}{2}y-\frac{13}{2} \\$

Substitute $\frac{5y-13}{2}\\$ for x in the other equation, 3x + 4y = 15.

$3\left(\frac{5}{2}y-\frac{13}{2}\right)+4y=15 \\$

Multiply 3 times $\frac{5y-13}{2}\\$ .

$\frac{15}{2}y-\frac{39}{2}+4y=15 \\$

Add $\frac{15y}{2} \\$ to 4y.

$\frac{23}{2}y-\frac{39}{2}=15 \\$

Add $\frac{39}{2}\\$ to both sides of the equation.

$\frac{23}{2}y=\frac{69}{2} \\$

Divide both sides of the equation by 23/2, which is the same as multiplying both sides by the reciprocal of the fraction.

$\large \underline{ \underline{ \sf \: y=3 }}$

Substitute 3 for y in $x=\frac{5}{2}y-\frac{13}{2}\\$ . Because the resulting equation contains only one variable, you can solve for x directly.

$x=\frac{5}{2}\times 3-\frac{13}{2} \\$

Multiply 5/2 times 3.

$x=\frac{15-13}{2} \\$

Add $-\frac{13}{2}\\$ to $\frac{15}{2}\\$ by finding a common denominator and adding the numerators. Then reduce the fraction to its lowest terms if possible.

$\large\underline{ \underline{ \sf \: x=1 }}$

The system is now solved. The value of x & y will be 1 & 3 respectively.

$\huge\boxed{ \boxed{\bf \: x=1, \: y=3 }}$

8 0

2 years ago

for the following questions, determine how many solutions each equation has. if one solution, state the value of x. x+6+8=2x-x+1

vichka [17]

Answer:

infinite solutions

Step-by-step explanation:

x+6+8=2x-x+14

x+6+8=x+14

x+14=x+14

14=14

x=x

plug in any number

2+6+8=2(2)-2+14

16=16

another example

8+6+8=2(8)-8=14

22=22

5 0

3 years ago

Which of the following best describes the relationship between the variables on the scatter plot below?

CaHeK987 [17]

Answer:

A. negative correlation

Step-by-step explanation:

Let two variables x and y, the correlation coefficient r measure to what degree the variables x and y are related.

--- If this coefficient is positive then the relationship will be positive. This means that even an increase in the variable x will produce an increase in the variable y. In the dispersion diagram the points will be grouped, simulating a line of positive slope.

--- If this coefficient is negative then the relation will be negative. This means that even an increase in the variable x will produce a decrease in the variable y. In the dispersion diagram the points will be grouped, simulating a negative slope line.

In the diagram shown it can be noted that as the variable x increases the variable y decreases.

Therefore it can be concluded that the correlation between x and y is negative. The correct option is option A

4 0

3 years ago

HELP‼️‼️‼️‼️‼️‼️ 1. If 8x + 4y = 44, what is the value of 6x + 3y?

Gnom [1K]

Answer:

33.

Step-by-step explanation:

8x + 4y = 44

4(2x + y) = 44

2x + y = 44/4 = 11.

6x + 3y

= 3(2x + y)

= 3 * 11

= 33.

8 0

2 years ago

Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the corre

sveticcg [70]

Answer:

Oh lordy I hope this is correct

Step-by-step explanation:

Type: Irrational Numbers. Example: 1.17513698...

Type: Natural Numbers. Example: 56

Type: Rational Numbers: Example: 1/3

Type: Integers. Example: -5

Type: Whole Numbers. Example: 0

6 0

3 years ago