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3 years ago

Which of these is a correct identity? x + 4x = 5x 6x = 18 2x + 1 = 7 7x + 9 = x

Mathematics

1 answer:

dolphi86 [110]3 years ago

7 0

Answer:

x + 4x = 5x

Step-by-step explanation:

An identity is a mathematical equation that is always true (here - for all possible x's).

a). x + 4x = 5x; this is true, because for any possible x

x+4x = (1 + 4)x = 5x; there's not much to add.

b). 6x=18; evaluates to

x = 3; so it only works for one x, not all possible xs.

c). 2x + 1 = 7

2x = 6

x = 3; so it only forks for one x

d). 7x + 9 = x

6x + 9 = 0; we could compute the exact x it works for from here, but suffice to say this doesn't work for x = 0.

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On a coordinate plane, 2 straight lines are shown. The first solid line has a positive slope and goes through (0, negative 2) an

ValentinkaMS [17]

The system of linear inequalities that is represented by the graph is C. y > x – 2 and x + 2y < 4.

<h3>How to get the equation?</h3>

The first thing to to find the slope. This will be:

m = y2 - y1/x2 - x1

m = 0+2/2-0

m = 2

The equation in slope intercept form will be:

y = mx + b. The inequality will be y > x - 2.

Again, the slope will be:

= (0 - 2)/(4 - 0)

= -1/2

The equation will be -1/2x + 2.

Multiply both sides by 2.

2y < -x + 4

x + 2t < 4

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7 0

2 years ago

Find the length of ladder

makkiz [27]

Answer:

33 feet

Step-by-step explanation:

Use SOHCAHTOA to determine which trigonometric function to use:

sin(65)=30/x

sin(65)x=30

x=30/sin(65)

x=33.1

So the length of the ladder rounded to the nearest foot is 33 feet

5 0

3 years ago

Help! How would I solve this trig identity?

NeTakaya

Using simpler trigonometric identities, the given identity was proven below.

<h3>How to solve the trigonometric identity?</h3>

Remember that:

$sec(x) = \frac{1}{cos(x)} \\\\tan(x) = \frac{sin(x)}{cos(x)}$

Then the identity can be rewritten as:

$sec^4(x) - sen^2(x) = tan^4(x) + tan^2(x)\\\\\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)} = \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)} \\\\$

Now we can multiply both sides by cos⁴(x) to get:

$\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)} = \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)} \\\\\\\\cos^4(x)*(\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)}) = cos^4(x)*( \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)})\\\\1 - cos^2(x) = sin^4(x) + cos^2(x)*sin^2(x)\\\\1 - cos^2(x) = sin^2(x)*sin^2(x) + cos^2(x)*sin^2(x)$