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3 years ago

I suck at basic Geometry. ( episode 2)

Mathematics

2 answers:

natali 33 [55]3 years ago

7 0

Answer:

B and C

Step-by-step explanation:

Triangles are similar if they have the same angles and their sides are proportional

mixer [17]3 years ago

5 0

The answer is B and c

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? m∠ABD = m∠ABC AB ≅ BC B is the midpoint of DC. m∠DBC = 90°

Misha Larkins [42]

Answer:

50*

Step-by-step explanation:

5 0

2 years ago

Ana ha comprado libros, todos del mismo precio, por valor de 120 euros. El librero le regala 3 libros por lo que cada libro le c

lidiya [134]

Answer:

El primer paso será darle un nombre a nuestras variables:

x= Numero de libros comprados inicialmente

y=Precio inicial de los libros

Ahora analizamos el enunciado,

Lorena ha comprado libros todos del mismo precio por valor de 120 €

x*y=120 € (1)

El librero le regala 3 libros por lo que en realidad cada libro que cuesta 2 € menos

(x+3)(y-2)=120€ (2)

Tenemos entonces dos ecuaciones con dos incógnitas, así que podemos resolver,

Despejamos en (1)

x=120/y

Sustituimos en (2)

(120/y +3)(y-2)=120

120 - 240/y + 3y -6 =120

3y-240/y =120-120+6

3y -240/y =6

y- 80/y=6

y²-80=6y

y²-6y-80=0

Resolvemos la ecuación de segundo grado

a=1

b=-6

c=-80

Aplicando la resolvente,

(6+- √36+320)/2

6+-√356/2

(6+-18,86)/2

Como el valor de y no puede ser negativo la unica respuesta válida será:

y=12,43

Cada libro le costo 12,43€

Sustituyendo en (1)

x=120/12,43

x=9,65 como no puede ser un número racional

x=9

Lorena ha comprado 9 libros

6 0

3 years ago

Please help math questions put number with answers please

natita [175]

Answer:

See below for answers

Step-by-step explanation:

Problem 1

$\frac{1}{sin\theta}=2cos\theta\: ; \: 0\leq\theta < 2\pi\\\\1=2sin\theta cos\theta\\\\1=sin2\theta\\\\\frac{\pi}{2}+2\pi n=2\theta\\ \\\frac{\pi}{4}+\pi n=\theta\\ \\\theta=\bigr\{\frac{\pi}{4},\frac{3\pi}{4},\frac{5\pi}{4},\frac{7\pi}{4}\bigr\}$

Therefore, the second option is correct.

Problem 2

$cos(2x)+1=sin(x)+2\:;\: 0\leq x < 2\pi\\\\1-2sin^2x+1=sin(x)+2\\\\-2sin^2x=sin(x)\\\\0=2sin^2x+sinx\\\\0=sinx(2sinx+1)$

$0=sinx\\\\x=\pi n\\\\x=0,\pi$

$0=2sinx+1\\\\-1=2sinx\\\\-\frac{1}{2}=sinx\\ \\x=\frac{7\pi}{6}+2\pi n,\frac{11\pi}{6}+2\pi n\\\\x=\frac{7\pi}{6},\frac{11\pi}{6}$

Therefore, the solution set is $x=\bigr\{0,\pi,\frac{7\pi}{6},\frac{11\pi}{6}\bigr\}$ , making the second option correct.

Problem 3

$2cos^2x=-cosx\: ;\: 0^\circ\leq x < 360^\circ\\\\2cos^2x+cosx=0\\\\cosx(2cosx+1)=0$

$cosx=0\\\\x=\frac{\pi}{2}+\pi n\\ \\x=90^\circ+180n^\circ\\\\x=90^\circ,270^\circ$

$2cosx+1=0\\\\2cosx=-1\\\\cosx=-\frac{1}{2}\\\\x=\frac{2\pi}{3}+2\pi n,\frac{4\pi}{3}+2\pi n\\ \\x=120^\circ+360n^\circ,240^\circ+360n^\circ\\\\x=120^\circ,240^\circ$

Therefore, the solution set is $x=\bigr\{90^\circ,120^\circ,240^\circ,270^\circ\bigr\}$ , making the fourth option correct

7 0

2 years ago

What is the solution to the inequality below?

madam [21]

Answer:

C. x < 25 and x ≥ 0

Step-by-step explanation:

Fastest and easiest way to do this is to graph the inequality and find out the lines.

8 0

3 years ago

What are the steps to this problem (and the answer?)

Svetradugi [14.3K]

Answer:

$(25 {x}^{2} + 20xy + 16 {x}^{2} )(5x - 4y) = \\ 125 {x}^{3} + 100 {x}^{2} y + 80x {y}^{2} - 100 {x}^{2} y \\ - 80x {y}^{2} - 64 {y}^{3} = \\ 125 {x}^{3} - 64 {y}^{3} \\ please \: give \: brainliest$

5 0

3 years ago