Someone pls help me on 3 and 4!!!!!! Mark you as

Solve 5x^2 - 7x + 2 = 0 by completing the square.

Reika [66]

Answer: The correct option is (c) $\dfrac{49}{100}.$

Step-by-step explanation: We are given to solve the following quadratic equation by the method of completing the square:

$5x^2-7x+2=0~~~~~~~~~~~~~~~~~~~(i)$

Also, we are to find the constant added on both sides to form the perfect square trinomial.

We have from equation (i) that

$5x^2-7x+2=0\\\\\Rightarrow x^2-\dfrac{7}{5}x+\dfrac{2}{5}=0\\\\\\\Rightarrow x^2-2\times x\times \dfrac{7}{10}+\left(\dfrac{7}{10}\right)^2+\dfrac{2}{5}=\left(\dfrac{7}{10}\right)^2\\\\\\\Rightarrow \left(x-\dfrac{7}{10}\right)^2=\dfrac{49}{100}-\dfrac{2}{5}\\\\\\\Rightarrow \left(x-\dfrac{7}{10}\right)^2=\dfrac{49-40}{100}\\\\\\\Rightarrow \left(x-\dfrac{7}{10}\right)^2=\dfrac{9}{100}\\\\\\\Rightarrow x-\dfrac{7}{10}=\pm\dfrac{3}{10}\\\\\\\Rightarrow x=\pm\dfrac{3}{10}+\dfrac{7}{10}.$

So,

$x=\dfrac{3}{10}+\dfrac{7}{10},~~~~~~~~x=-\dfrac{3}{10}+\dfrac{7}{10}\\\\\\\Rightarrow x=\dfrac{10}{10},~~~~~~~~\Rightarrow x=\dfrac{-3+7}{10}\\\\\\\Rightarrow x=1,~-\dfrac{2}{5}.$

Thus, the required solution is $x=1,~-\dfrac{2}{5}.$ and the value of the constant added is $\dfrac{49}{100}.$

Option (c) is correct.

3 0

3 years ago

Boris can type 56 words in 8 minutes. What is his rate in words per minute?

amid [387]

7 words per minute! :) Hope I helped!!

7 0

3 years ago

Read 2 more answers

Liz's website has been getting more popular, primarily through word-of-mouth advertising. Each month, she sees a 5% increase in

muminat

Step-by-step explanation:

31357.85046

5 0

2 years ago

What is the value of x+y?<br><br> Eight grade math

atroni [7]

Hello! The value of x+y is 12

Make sure to read an explanation so you can understand the solution better.

Any questions about the answer and explanation can be asked through comments.

Step-by-step explanation:

We can simply solve the system of equations by substituting x = 3y in the first equation

$\large{2x + 2y = 24} \\ \large{2(3y) + 2y = 24} \\ \large{6y + 2y = 24} \\ \large{8y = 24} \\ \large{y = 3}$

Therefore, the value of y is 3. Then we substitute the value of y in x = 3y.

$\large{x = 3y} \\ \large{x = 3(3)} \\ \large{x = 9}$

Therefore, the value of x is 9.

Since you want to find x+y, simply add 9 and 3 as we get 12.

Therefore x+y = 12.

6 0

2 years ago

The area of the triangle below is 16.28 square feet. What is the<br> length of the base?<br> 3.7 ft

Deffense [45]

Answer:

Given a rectangle with length l and width w, the formula for the area is: A = lw (rectangle). That is, the area of the rectangle is the length multiplied by the width. As a special case, as l = w in the case of a square, the area of a square with side length s is given by the formula: A = s2 (square).

3 0

2 years ago