Answer:
49
Step-by-step explanation:
5^2 - 4(-3)(2)
5^2 - 4(-6)
25 - 4(-6)
25 - (-24)
49
Hope this helps!
Answer:
86%
Step-by-step explanation:
Let g represent the mean mark for the 10 girls in the class. Then the mean mark for the class was ...
10g +20(62%) = 30(70%)
g = 3(.7) -2(.62) . . . . . . . . . divide by 10 and subtract 2(.62)
g = .86 = 86%
The mean mark for girls was 86%.
_____
You can do this in your head if you consider it in terms of deviations from the mean. The second equation above can be rewritten and factored as ...
g = 70% +2(70% -62%)
That is, because there are 2 boys for every girl, the girl's score is above the mean by an amount that is 2 times the amount that the boy's score is below the mean. The boys' score is below by 8%, so the girls' score is above by 16%, so is 86%.
The error made by zacharias in solving the quadratic equation 0 = -2x² + 5x - 3 using quadratic formula is; the 2 in the numerator should be –2.
<h3>Quadratic equation</h3>
There are four methods of solving quadratic equation. Namely;
- Factorization method
- Completing the square method
- Graphical method
- Formula method
0 = -2x² + 5x - 3
x = -b ± √b² - 4ac / 2a
where,
x = -b ± √b² - 4ac / 2a
x = -5 ± √5² - 4(-2)(-3) / 2(-2)
= -5 ± √25 - (24) / -2
= -5 ± √1 / -2
= -5/2 ± 1/2
= -5/2 - 1/2 or x = -5/2 + 1/2
= -5-1 / 2 or -5+1/ 2
x = -6/2 or -4/2
x = -3 or -2
Therefore, the solution to the quadratic equation is x = -3 or -2
Learn more about quadratic equation:
brainly.com/question/1214333
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Answer:
60
Step-by-step explanation:
Assuming that all 54 shelves hold the same number of books its just a matter of dividing them (or sharing them equally) on each shelf.
3240 / 54 = 60
Each shelf holds 60 books.
The answer to your question is Y=12
