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
Distributive Property: a ( b + c) = (a*b) + (a*c)
b) x(x + 9) = x*x + 9*x
= x² + 9x
c) x² - 18x
x² = x * x
18x = 18 *x
G C F = x
Greatest common factor in both the terms is 'x'.Take the common variable from both the terms.
x² - 18x = x*x - 18*x
= x (x - 18)
Standard form. Factored form
x² x*x
x² + 9x x(x +9)
x² - 18x x(x - 18)
-x² + 10x x(-x + 10) = x(10 -x)
-x² - 2.75x -x(x + 2.75)
Tammy's sample may not be considered valid because, on the first hand, it is said that she only asked students from her " Math Class".
If she wants to have a survey to find out the favorite subject of the students at her school, she must conduct a survey involving all the students in her school, not just in her class. What she did is just subjective. She should use a tally listing the different subjects and compare the number of students per subject. This way, she can have an objective representation of the least liked subjects and the most liked subjects of the students on her school.
Illustrating her survey through statistics may be more reliable and valid because it shows frequencies in which she can calculate easily and accurately the percentage of the number of students per subject, in a more objective manner.
Hi there
1+0.035=(1+r/360)^360
Solve for r
R=(((1.035)^(1÷360)−1)×360)×100
R=3.44%
