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Aleks [24]
3 years ago
12

What is the value of 2x^2+6x-9 when x = 3

Mathematics
2 answers:
viva [34]3 years ago
8 0

Answer:

45

Step-by-step explanation:

We have the equation 2x² + 6x + 9 and are asked to find the value when x =3.

To solve this, all we need to do is substitute all variables with "x" to 3. Then do the properties :

2x² + 6x + 9

2(3)² + 6(3) + 9

Do exponents first :

2(9) + 6(3) + 9

Now multiply the numbers with parenthesis next to them :

18 + 18 + 9

Add to get the answer :

45

klemol [59]3 years ago
5 0

Answer:

27

Step-by-step explanation:

We have the equation:

2x^2+6x-9

If x = 3, we can substitute 3 in for the x values.

We get the equation:

2(3^{2}) + 6(3) - 9

Using PEMDAS:

First, evaluate the power.

3^2 = 9

Then, multiply the numbers.

2 x 9 + 6 x 3 - 9

We get:

18 + 18 - 9

Simplify.

18 + 18 = 36

36 - 9 = 27

Hope this helps.

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Answer:

Yes, Fiona is correct

Step-by-step explanation:

WHen the pythagorean theorem is applied to the side lengths (2^2 + 4^2 = c^2), the result for c^2 is 20. The correct answer would be sqrt.20. But Fiona is also correct becuase sqrt of 20 can be simplified to sqrt.4 * sqrt.5; which equals 2*sqrt.5

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34 times 50 plus 34 divided by 60 equals 28.9
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7x + 2y = 24<br>8x + 2y = 30​
bagirrra123 [75]
(8x + 2y) - (7x + 2y) = 30 - 24

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The distance between X and Y is 6 1/2 units. Which number could represent the point Y?
tiny-mole [99]

Answer:

\huge\boxed{\sf 3.5}

Step-by-step explanation:

Distance = \sf 6 \frac{1}{2} \ units = 6.5 \ units

Here X is -3

So,

Point Y = -3 + 6.5 = 3.5

\rule[225]{225}{2}

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<h3>~AH1807</h3>
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Graph the function.
RideAnS [48]

Answer:

\displaystyle{y=-3x-1}

Step-by-step explanation:

I have two methods: <u>standard-learning</u> which will explain overall mathematically - basically formula, etc. - while the other one <u>trick-tips</u> method will rely on choices rather mathematical calculations but with explanation on <em>why</em> and <em>how.</em>

<h3>Standard-Learning</h3>

First, let’s pick two points that are integers since they are easily to be found via graphs. We see that (-1,2) and (0,-1) is a part of the graph so now we finally have picked two points for our calculations.

When we have finally picked two points, we will be using them for <u>slope calculation</u>. This part is <u>crucial</u> for finding an equation of a line because a line has to contain slope in its equation.

To calculate the slope, we use rise over run formula which is:

\displaystyle{\dfrac{\Delta y}{\Delta x} = \dfrac{y_2-y_1}{x_2-x_1}}

Note that \displaystyle{\Delta} is delta - in both mathematic and physics, it means <u>changes in</u>.

So, we will be using those two points that we have picked to substitute in the slope formula. Let’s determine that \displaystyle{(x_2,y_2)=(-1,2)} and \displaystyle{(x_1,y_1)=(0,-1)}.

Therefore, our slope will be:

\displaystyle{m=\dfrac{2-(-1)}{-1-0}}\\\\\displaystyle{m=\dfrac{2+1}{-1}}\\\\\displaystyle{m=-3}

Next, find the y-intercept. From the graph, we see that the graph intercepts at (0,-1) which is y-intercept so we will only use y-value. Hence, b = -1.

From the slope-intercept form:

\displaystyle{y=mx+b}

Substitute m (slope) = -3 and b (y-intercept) = -1. Hence, the equation of line is:

\displaystyle{y=-3x-1}

<h3>Fast Way (Trick-Tips)</h3>

Relying on choices and knowledge of graph, notice that there are slopes of 3 and -3.

Keep in mind that if slope is negative, it will decrease down and if slope is positive, it will increase up.

Therefore, cut off all choices with positive slopes which are 1 and 3. We are now left with 2 and 4.

Next, look at the graph and tell its y-intercept. It intercepts y at y = -1 so we take value of -1.

So choice 4 is cut off and now we have choice 2 as the answer.

Learn More:

brainly.com/question/27514958 - Find the line equation with given points

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