A. Standard form because there is only one digit in front of the decimal point.
The formula to find the discriminant equals D = b^2-4ac.
(Quadratic equations have the formula ax^2+bx+c. A = -1, B = +4, C = -2.)
D = 4^2-4(-1)(-2). 8-8 = 0.
0 = 1 solution
-D = 0 solutions
+D = 2 solutions
The discriminant equals 0, also establishing that if you were asked to find the solutions, there would only be one.
Answer: 4) 157
Step-by-step explanation:
We know that there is no association between the grade level and the andedness, then we should find that the ratio between left handeds and right handed is the same for both grades.
In 7-th grade we have:
Left handed : 11
Right handed: 72
The ratio is 11/72 = 0.14
Then, the ratio for the 8-th graders must be about the same:
Left handed: 24
Right handed: X
Ratio: 24/X
Let's start with the bigger option, X = 157.
24/157 = 0.15
Ok, we now see that with the bigger option we obtained almost the same ratio (if we use the smaller values for X, we will get a ratio bigger than 0.15, so 0.15 is the better aproximation that we can find to the 0.14 of the 7-th graders)
Then the correct option is 4) 157
