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question:Given two lines l_{1}: 3x+4y2=0 and l_{2}: 2x+y+2=0 with the intersection point P, find the equations of the lines that satisfy the following conditions: (1) The line passes through point P and the origin. (2) The line passes through point P and is perpendicular to line l_{3}: x2y1=0.
answer:(1) First, we find the intersection point P by solving the system of equations for lines l_{1} and l_{2}: begin{cases} 3x+4y-2=0 2x+y+2=0 end{cases} Solving this system, we find x=-2 and y=2. So the intersection point is P(-2, 2). Now we need to find the line passing through P(-2, 2) and the origin. The slope of this line can be found using the formula m = frac{y_2 - y_1}{x_2 - x_1} where (x_1, y_1) and (x_2, y_2) are the coordinates of two points on the line. In this case, we have (x_1, y_1) = P(-2, 2) and (x_2, y_2) = (0, 0) (origin). Substituting these values into the formula, we get: m = frac{2 - 0}{-2 - 0} = -1 Using the point-slope form of a linear equation, y - y_1 = m(x - x_1), we can write the equation of the line as: y - 2 = -1(x + 2) Simplifying this equation, we get the final answer: boxed{x + y = 0} (2) First, we find the slope of line l_{3}: x - 2y - 1 = 0. Rewriting this equation in slope-intercept form (y = mx + b), we have y = frac{1}{2}x - frac{1}{2}. So the slope of line l_{3} is m_{l_3} = frac{1}{2}. Since the line we are looking for is perpendicular to line l_{3}, its slope m_{l} will be the negative reciprocal of the slope of line l_{3}. That is, m_{l} = -frac{1}{m_{l_3}} = -frac{1}{frac{1}{2}} = -2 Now we use the point-slope form of a linear equation with point P(-2, 2) and slope m_{l} = -2 to find the equation of the line: y - 2 = -2(x + 2) Simplifying this equation, we get the final answer: boxed{2x + y + 2 = 0}
question:have 9 pennies, 4 nickels, and 3 dimes. How much money do I have?
answer:To calculate the total amount of money you have, you need to multiply the number of each type of coin by its value and then add up all the values. Pennies: 9 pennies × 0.01 = 0.09 Nickels: 4 nickels × 0.05 = 0.20 Dimes: 3 dimes × 0.10 = 0.30 Now, add up all the values: 0.09 (pennies) + 0.20 (nickels) + 0.30 (dimes) = 0.59 You have a total of boxed{0.59} .
question:On a small train with five individual cars, Jess, Lisa, Mark, Nina, and Owen all took a ride. Nina sat in the last car. Jess sat right in front of Owen. Mark sat somewhere ahead of Jess. Between Lisa and Mark, there was at least one empty car. Determine who was in the second car from the front. textbf{(A) }text{Jess} qquad textbf{(B) }text{Lisa} qquad textbf{(C) }text{Mark} qquad textbf{(D) }text{Nina}qquad textbf{(E) }text{Owen}
answer:1. **Identify the positions and constraints**: - The train cars are arranged in a line: square_1 square_2 square_3 square_4 square_5. - Nina is in the last car: square_1 square_2 square_3 square_4 N. 2. **Place Jess and Owen**: - Jess is right in front of Owen, making consecutive placements: - square_1 square_2 square_3 J O N - square_1 square_2 J O square_4 N - square_1 J O square_3 square_4 N 3. **Position Mark ahead of Jess**: - Mark must be ahead of Jess, limiting his positions: - square_1 square_2 square_3 J O N allows Mark in square_1 or square_2. - square_1 square_2 J O square_4 N allows Mark only in square_1. - square_1 J O square_3 square_4 N disallows Mark completely. 4. **Respect the gap between Lisa and Mark**: - There must be at least one car between Lisa and Mark: - The configuration square_1 square_2 J O square_4 N with Mark in square_1 allows Lisa to be in square_4. - Other configurations are not valid as they do not satisfy the gap condition. 5. **Final arrangement**: - The valid arrangement is square_1 M square_2 J O L N. 6. **Who is in the second car?**: - Mark is in the second car from the front. The person in the second car is text{Mark}. Conclusion: The solution is consistent with all given conditions. Mark is indeed the occupant of the second car according to the verified solution. The final answer is boxed{textbf{(C) }text{Mark}}
question:Given the vectors overrightarrow{a}=(1, 2), overrightarrow{b}=(x, 1), let overrightarrow{u}= overrightarrow{a}+ overrightarrow{b} and overrightarrow{v}= overrightarrow{a} overrightarrow{b}, (Ⅰ) If overrightarrow{u}parallel overrightarrow{v}, find the value of the real number x; (Ⅱ) If overrightarrow{u}perp overrightarrow{v}, find the value of the real number x.
answer:Given that overrightarrow{a}=(1, 2), overrightarrow{b}=(x, 1), overrightarrow{u}= overrightarrow{a}+ overrightarrow{b}, and overrightarrow{v}= overrightarrow{a}- overrightarrow{b}, we can compute overrightarrow{u} and overrightarrow{v} as follows: overrightarrow{u} = (1 + x, 3) overrightarrow{v} = (1 - x, 1) (Ⅰ) Since overrightarrow{u} is parallel to overrightarrow{v}, their components must be proportional. Therefore, we have the proportion: frac{1 + x}{1 - x} = frac{3}{1} Cross-multiplying gives us: (1 + x) = 3(1 - x) Expanding the equation: 1 + x = 3 - 3x Moving all terms involving x to one side and constant terms to the other side, we get: x + 3x = 3 - 1 Combining like terms: 4x = 2 Dividing both sides by 4 gives us: x = frac{1}{2} Thus, the value of x when overrightarrow{u} is parallel to overrightarrow{v} is: boxed{x = frac{1}{2}} (Ⅱ) Since overrightarrow{u} is perpendicular to overrightarrow{v}, their dot product must be zero: (1 + x)(1 - x) + 3 cdot 1 = 0 Expanding the equation: 1 - x^2 + 3 = 0 Rearranging the terms: x^2 = 4 Taking the square root of both sides gives us two solutions: x = 2 text{ or } x = -2 Therefore, the values of x when overrightarrow{u} is perpendicular to overrightarrow{v} are: boxed{x = 2 text{ or } x = -2}