Select the correct answer.

3x - 3y = 9 and x + 3y = 12 <br> Elimination

Firlakuza [10]

Answer:

$x=5.25,y=2.25$

Step-by-step explanation:

We can add the two equations to eliminate the variable $y$ and solve for $x$ :

$3x-3y+x+3y=9+12$

$4x=21$

$x=5.25$

Now, we can use substitution to solve for $y$ :

$x+3y=12$ (given)

$5.25+3y=12$

$3y=12-5.25$

$=6.75$

$y=2.25$

Hope this helps :)

8 0

3 years ago

The function f(x) = –x2 – 4x + 5 is shown on the graph. On a coordinate plane, a parabola opens down. It goes through (negative

sertanlavr [38]

The true statement about the function f(x) = -x² - 4x + 5 is that:

The range of the function is all real numbers less than or equal to 9.

<h3 /><h3>What is the domain and range for the function of y = f(x)?</h3>

The domain of a function is the set of given values of input for which the function is valid and true.

The range is the dependent variable of a given set of values for which the function is defined.

The domain of the function: f(x) = -x² - 4x + 5 are all real number from -∞ to +∞

For a parabola ax² + bx + c with the vertex $\mathbf{(x_v,y_v)}$

If a < 0, then the range is f(x) ≤ $\mathbf{y_v}$

If a > 0, then the range f(x) ≥ $\mathbf{y_v}$

Here; a = -1,

The vertex for an up-down facing parabola for a function y = ax² + bx + c is:

$\mathbf{x_v = -\dfrac{b}{2a}}$

Thus,

vertex $\mathbf{(x_v,y_v)}$ = (-2, 9)

Range: f(x) ≤ 9

Therefore, we can conclude that the range of the function is all real numbers less than or equal to 9.

Learn more about the domain and range of a function here:

brainly.com/question/26098895

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5 0

2 years ago

Fred the owl is looking down at a 67° angle from the top of a tree that is 15 ft tall, when he spots a bird on the ground. How f

guapka [62]

Answer:

Fred C. 16.30 ft

Gary B. 169.67 m

Step-by-step explanation:

Fred the owl...

Always <u>draw a diagram first</u> (see diagram below). We assume trees are perpendicular (at 90°) to the ground. The situation forms a right-angle triangle.

We need to <u>find "x"</u>, which is the direct distance between the owl and the bird. "x" is also the hypotenuse, which is the longest side in a right-angle triangle. Since we know a side and an angle, we can find the hypotenuse using primary trigonometry ratios.

∠B will be the angle of reference (the angle we are "talking" about). The side we know is opposite to ∠B (15ft). We know it's opposite because it's not touching the angle. The side we need to find is the hypotenuse.

<u>Use the trig. ratio sine</u> because it has opposite and hypotenuse in it. The general formula is:

sinθ = opp/hyp

θ means the angle, and we know it is 67°.

Replace all the information you know:

sinB = opp/hyp

sin67° = (15ft) / x Isolate "x". Rearrange the equation.

xsin67° = (15ft) Divide both sides by sin67°

x = (15ft) / sin67°

x = 16.295... ft Exact answer in decimals

x ≈ 16.30 ft Rounded to nearest hundredth

Therefore Fred the owl is 16.30 feet from the bird.

Gary spots a monkey...

Draw a diagram first (see below). G is Gary, M is the monkey, T is the bottom of the Sears Tower. We need to <u>find "x"</u>, which is the distance between the monkey and the bottom of the tower.

The angle of reference is M, which is 69°. We need to find the adjacent side and we know the opposite side. <u>The trig. ratio that has adjacent and opposite is tangent.</u>

tanθ = opp/adj

Replace all the information you know:

tanM = opp/adj

tan69° = (442m) / x Rearrange the formula to isolate "x"

xtan69° = 442m Divide both sides by tan69°

x = 442m / tan69° Solve by dividing

x = 169.6679.... m Exact decimal answer

x ≈ 169.67m Rounded to the nearest hundredth

Therefore the monkey is 169.67 metres from the tower.

Remember all the trig. ratios using the acronym SohCahToa.

o = opposite side

a = adjacent side