Factorise fully 21x² +25x =4

If Diana walks forward and her angle looking to the top of the building changes to 40°, how much closer is she to the building?

elena55 [62]

The closer Diana gets to the building, the smaller the angle becomes

Diana is 17.6 feet closer to the building

<h3>How to calculate the distance from the building</h3>

To calculate the distance between her and the building, we make use of the following tangent ratio

$\tan(\theta) = \frac{h}{d}$

Where:

$\theta = 40^o$
h represents the height of the building; h = 130
d represents the distance from the building

So, we have:

$\tan(40) = \frac{130}{d}$

Make d the subject

$d = \frac{130}{\tan(40)}$

Evaluate tan(40)

$d = \frac{130}{0.8391}$

$d = 154.93$

Initially, Diana is at a distance of 172.53.

The difference in both distance is:

$\Delta d = 172.53 - 154.93$

$\Delta d = 17.6$

Hence, Diana is 17.6 feet closer to the building

Read more about trigonometry ratios at:

brainly.com/question/4326804

7 0

2 years ago

(3x+2)∧2=9 how do i solve this in the square root property

Irina18 [472]

$(3x+2)^2=9 \\\\9x^2+12x+4-9=0\\\\9x^2+12x-5=0\\\\a=9,\ \ b=12, \ \ c=-5$

$x_{1}=\frac{-b-\sqrt{b^2-4ac}}{2a}=\frac{-12-\sqrt{12^2-4 \cdot9 \cdot (-5)}}{2 \cdot 9}=\frac{-12-\sqrt{144+180}}{18}=\\\\=\frac{-12-\sqrt{324}}{18}=\frac{-12-18}{18}=\frac{-30}{18}=-\frac{5}{3}\\\\x_{2}=\frac{-b+\sqrt{b^2-4ac}}{2a}=\frac{-12+\sqrt{12^2-4 \cdot9 \cdot (-5)}}{2 \cdot 9}=\frac{-12+18}{18}=\frac{6}{18}=\frac{1}{3} \\\\Answer: \ x=-\frac{5}{3}\ \ and \ \ x=\frac{1}{3}$

6 0

3 years ago

Five cupcakes and two cookies cost $19.75. Two cupcakes and four cookies cost $ 17.50.

alina1380 [7]

Answer:

Step-by-step explanation:

Let x and y represent the cost of a cupcake and cookie respectively.

Given that;

Five cupcakes and two cookies cost $19.75.

$5x+2y=19.75 ---------- 1$