Answer:
Student B is correct
Student A failed to distribute -4 and -6 when opening the brackets in the first step
Step-by-step explanation:
The solution Student A gave was:
2x - 4(3x + 6) = -6(2x + 1) - 4
2x - 12x + 6 = -12x + 1 - 4
-10x + 6 = -12x - 3
2x = -9
x = -4 _1 2 ( -4 1/2)
The solution Student B gave was:
2x - 4(3x + 6) = -6(2x + 1) - 4
2x - 12x - 24 = -12x - 6 - 4
-10x - 24 = -12x - 10
2x = 14
x = 7
Student B is correct.
Explanation of the error:
Student A failed to distribute -4 and -6 when opening the brackets in the first step.
That is,
2x - 4(3x + 6) = -6(2x + 1) - 4
To open this bracket, we will distribute, -4 and -6 so that we get
2x (-4 × 3x) + (-4 × +6) = (-6×2x) + (-6 × +1) - 4
Then we will get
2x -12x -24 = -12x -6 -4
Adding the like terms
-10x - 24 = -12x - 10
Collecting like terms
-10x + 12x = -10 + 24
∴ 2x = 14
x = 14 / 2
Hence,
x = 7
Answer:
26.8°
Step-by-step explanation:
The cosine of an angle is the ratio of the adjacent side of the triangle in which the angle is formed to the hypotenuses side of the triangle. The cosine of the angle gives the ratio of these sides. However, the arc cosine of the ratio gives the angle measured in degrees.
If cos B = 0.8926
then arc cosine 0.8926 which may be expressed as cos-1 0.8926 will give the value of B.
B = cos-1 0.8926
= 26.8°
108=2x-4(2x-9)
108=2x-8x+36
108=-6x+36
-36 -36
72=-6x
72/-6=-6x/-6
-12=x
1 and 1/2 is the right one
The total of two whole numbers one after another is 33. for example 10 + 11 (two consecutive integers) = 21
