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3 years ago

Find the incorrect step in each solution and explain whit it is incorrect.

Mathematics

1 answer:

julsineya [31]3 years ago

3 0

Answer:

Step-by-step explanation:

Mai:

She subtracted 5x instead of distributing. This is incorrect, because since it is in ( ), it has to be multiplied by 3.

Correct: 3(5x + 9) = 15x + 27

12x + 3 = 15x + 27

Noah:

Added 15x instead of subtracting. This is incorrect, because to combine like terms on each side you would add a negative number and subtract a positive number.

Correct: 12x + 3 = 15x + 27

12x - 15x = 27 - 3

-3x = 24

x = 24 / -3

x = -8

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La solución de la operación 3/5+2/5+7/5 es a.7/5 b.12/5 C.9/5

gtnhenbr [62]

Answer:

la respuesta a la solución es b

Step-by-step explanation:

5 0

3 years ago

The sum of the diagonals of a rhombus is 5√2.

Alex

Greetings!
Let ABCD be a rhombus
AC + BD = 5√2 cm

Area of ABCD = Ar△ABD + Ar △BCD
$= \frac{1}{2} \times BD \times AO + \frac{1}{2} \times BD \times OC$
$= \frac{1}{2} BD (AO + OC)$
$\frac{1}{2} BD \times AC$

$So, \frac{ BD \times AC}{2} = 4 \: cm {}^{2}$
$BD \times AC = 8$
$Now, AC + \: BD = 5 \sqrt{2}$

Squaring both sides, we get
$AC {}^{2} + BD {}^{2} + 2 AC.BD =50$
$AC {}^{2} + BD {}^{2} + 2 \times 8 = 50$
$AC {}^{2} + BD {}^{2} = 50 - 16$
$AC {}^{2} + BD {}^{2} = 34$

In △AOB, we have
$OA {}^{2} + OB {}^{2} =AB {}^{2}$
$( \frac{ AC }{2} ) {}^{2} + ( \frac{ BD}{2} ) {}^{2} = AB {}^{2}$
$\frac{ AC {}^{2} } {4} + \frac{ BD {}^{2} }{4} = AB {}^{2}$
$AC {}^{2} + BD {}^{2} = 4 AB {}^{2}$
$34 = 4 AB {}^{2}$

Square rooting both sides
$\sqrt{34} = 2 AB$
$Perimeter = 4 \: AB \\ = 2 \times 2 \: AB \\ = 2 \: \times \sqrt{34 } \\ = 2 \sqrt{34 \: } units$ .

Hope it helps!

7 0

4 years ago

Expand. Your answer should be a polynomial in standard form. (3c + 2)(c^2-6c-4)

evablogger [386]

Answer:

After expanding the polynomial $(3c + 2)(c^2-6c-4)$ we get $3c^3-16c^2-24c-8$

Step-by-step explanation:

We need to expand the polynomial $(3c + 2)(c^2-6c-4)$

Multiply the terms:

$(3c + 2)(c^2-6c-4)\\=3c(c^2-6c-4)+2(c^2-6c-4)\\=3c^3-18c^2-12c+2c^2-12c-8\\=3c^3-18c^2+2c^2-12c-12c-8\\=3c^3-16c^2-24c-8$

So, after expanding the polynomial $(3c + 2)(c^2-6c-4)$ we get $3c^3-16c^2-24c-8$

3 0

3 years ago

What's 1.48 repeating as a

jolli1 [7]

Answer:

147/99

Step-by-step explanation:

(1.48 x 100) - 1 99

3 0

3 years ago

Geometry help!!

Nastasia [14]

You answer will be C, Angle Side Angle (ASA). Since you are given two lines parallel, then you know angle BCE and angle CEF are congruent using the reason of "If two lines are parallel then the alternate interior angles are congruent" (they are congruent because they are alternate interior angles). Also, angle CBF and angle BFE are congruent because they are both alternate interior angles.

P.S. the first pair of alternate interior angles is created by parallel lines BC and EF and the intersecting line BF. And the second pair is created by parallel lines BC and EF and intersecting line CE.

4 0

4 years ago