This is an arithmetic series, where S5 means the sum of the first 5 numbers in the series. The general formula is:
Sn = (n/2)(a1 + an)
So,
a1 = 1 + 5/2(1) = 3.5
a5 = 1 + 5/2(5) = 1.5
S5 = (5/2)(3.5+1.5)
S5 = 12.5
<em>The answer should be 12.5</em>
2 Answers:
- B) The lines are parallel
- C) The lines have the same slope.
Parallel lines always have equal slope, but different y intercepts.
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Explanation:
Let's solve the second equation for y
3y - x = -7
3y = -7+x
3y = x-7
y = (x-7)/3
y = x/3 - 7/3
y = (1/3)x - 7/3
The equation is in y = mx+b form with m = 1/3 as the slope and b = -7/3 as the y intercept. We see that the first equation, where y was already isolated, also has a slope of m = 1/3. The two equations of this system have the same slope. Choice C is one of the answers.
However, they don't have the same y intercept. The first equation has y intercept b = -4, while the second has b = -7/3. This means that they do not represent the same line. They need to have identical slopes, and identical y intercepts (though the slope can be different from the y intercept of course) in order to have identical lines. So we can rule out choice D and E because of this.
Because the two equations have the same slope, but different y intercepts, this means the lines are parallel. Choice B is the other answer.
Parallel lines never touch or intersect, which in turn means there is no solution point. A solution point is where the lines cross. We can rule out choice A.
I recommend using your graphing calculator, Desmos, GeoGebra, or any graphing tool (on your computer or online) to graph each equation given. You should see two parallel lines forming. I used GeoGebra to make the graph shown below.
Answer:
Option (c) is correct.
Step-by-step explanation:
See the attached figure.
Here, x + y = 10 cm. ............ (1)
The height h divides the whole right triangle into two different right triangles.
If we consider the height as h, then applying Pythagoras Theorem,
h² = 6² - x² {From small triangle} ........... (2)
Again, from large triangle we can write,
h² = 8² - y² .............. (3)
Now, from equation (2) and (3) we can write
6² - x² = 8² - y²
⇒ 36 - x² = 64 - (10 - x)² {From equation (1)}
⇒ 36 - x² = 64 - 100 - x² + 20x
⇒20x = 72
⇒ x = 3.6 cm.
So, from equation (1) we get, y = 10 - 3.6 = 6.4 cm.
Therefore, option (c) is correct. (Answer)
Step-by-step explanation:
18/24>20/24 you have to flip the sign to make it correct