Answer:
D.
Step-by-step explanation:
In order to eliminate, the numbers must eliminate. If the second equation is multiplied by 3, then the 3 and the -3 can be eliminated. Since it is multiple choice, we can plug in x = 12 and y = 10 to see if they are correct. 12 + 30 = 42 and 24 - 10 = 14, so D is correct.
Answer:Identity property
Step-by-step explanation:
Answer:
2.5
Step-by-step explanation:
The number of points Marco needs to bring his average up to 90% is 15points.
If there's a possible 25 possible points, and Marco has taken 5 quizzes;
Evidently, each quiz has weighs 5 points.
Mathematically;
- 2100 + 500x = 2250 + 450x
x = 3.
Therefore, he needs 5x points = 15 points to bring his average up to 90%.
Read more:
https://brainly.in/question/24249798
Pythagorean theorem- a²+b²=c²
so a= 3 b=6 c=hypotenuse
3²+6²=c²
9+36=45
square root of 45 is 6.708203932 so 7.1 (1dp) is the answer