4 x 7 is 28, and 8 x 7 is 56. You can use 4 x 7 to find 8 x 7 by multiplying that first and doubling that quotient.
Half of 56 is 28, therefore doubling that allows us to find the quotient of 8 x 7.
Answer:
Step-by-step explanation:
1). x² - 8x
To convert this expression into a perfect square trinomial,
x² - 2(4x) + 4² = (x - 2)²
Therefore , 4² = 16 should be added.
Option (4) is the answer.
2). x² + 2x = 3
x² + 2(1)(x) = 3
x² + 2(1)(x) + 1 = 3 + 1 [By adding 1 on both the sides]
(x + 1)² = 4
x + 1 = ±2
x = -3, -1
Option (1) is the answer.
3). 3x²- 18x = 21
x² - 6x = 7
x² - 2(3x) = 7
x² - 2(3x) + 3² = 7 + 3²
(x - 3)² = 7 + 9
(x - 3)² = 16
x - 3 = ±4
x = -1, 7
You didn't put the values..??
Answer: 35 additional teachers are needed
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Explanation:
We have 2470 students and the ratio of students to teachers is 26:1. This means that for every teacher, there are 26 students. Put another way, we can set up this ratio
2470/x = 26/1
where x is the number of teachers. Cross multiply and solve for x
2470/x = 26/1
2470*1 = 26*x
2470 = 26x
26x = 2470
26x/26 = 2470/26
x = 95
So we have 95 teachers currently
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Let y be the new number of teachers needed to bring the ratio down to 19:1
Using a similar idea as done above, we would have this ratio
2470/y = 19/1
Let's solve for y
2470/y = 19/1
2470*1 = 19*y
2470 = 19y
19y = 2470
19y/19 = 2470/19
y = 130
So we'll need 130 teachers to have the ratio be 19:1
The difference of the values is y - x = 130 - 95 = 35, which is the final answer. This is the additional amount of teachers needed.
Line segment of length k is divided into 3 equal parts.
so first segment is 0-k/3 and third segment is 2/3k-k
so mid-pt of 1st = k/6 and 3rd = 5/6k
so the distance in between = 5/6k-k/6 = 4/6k = 2/3k
