help em vs ạ từ 1-11

To solve the given math problem, we can follow these steps: 1. Câu 1: We need to find the correct conclusion for the given conditions. The correct answer is option B. To solve this, we can use the concept of cross multiplication for fractions. Given $\frac{a}{b} = \frac{c}{d}$ and $b \neq 0$, $d \neq 0$, and $b \neq \pm d$, then $\frac{a+c}{b+d}$ is also equal to $\frac{a}{b}$. Therefore, the correct conclusion is $\frac ab=\frac cd=\frac{a+c}{b+d}$. 2. Câu 2: We need to find the formula representing y in terms of x when x and y are directly proportional with a ratio of 2. The correct answer is option D. When two quantities are directly proportional, their relationship can be represented as $y=kx$, where k is the constant of proportionality. In this case, since the ratio is 2, the formula becomes $y=2x$. 3. Câu 3: We need to find the ratio when x=4 and y=-12 in a direct proportionality relationship. The correct answer is option A. The ratio of direct proportionality between x and y can be found using the formula $k = \frac{y}{x}$. Substituting x=4 and y=-12 gives us $k = \frac{-12}{4} = -3$. 4. Câu 4: We need to determine the intersection point of three medians in a triangle. The correct answer is option C. The intersection point of three medians in a triangle is its centroid or trọng tâm. 5. Câu 5: We need to express the perimeter of a rectangle with length 9cm and width 6cm using an expression. The correct answer is option D. The perimeter (chu vi) of a rectangle with length l and width w can be expressed as $P=2(l+w)$. Substituting l=9cm and w=6cm gives us $P=(6+9)\times2 = (6+9)\times2(cm)$. 6. Câu 6: We need to identify which polynomial represents a single-variable polynomial. The correct answer is option A. A single-variable polynomial contains only one variable raised to non-negative integer powers, without any other variables involved. 7. Câu 7: We need to find the root(s) of the polynomial f(x)=2x-2. The correct answer is -1. To find roots, we set f(x) equal to zero and solve for x: $f(x)=0$ $2x-2=0$ $2x=2$ $x=1$ 8. Câu 8: We need to determine the degree of polynomial P(x)=-2x^5-3x^4+2x^5-x^2+3. The correct answer is 5. The degree of a polynomial is determined by finding the highest power of its variable term. 9. Câu 9: We need to identify which set could represent the lengths of sides in a triangle. Options A and C are both valid answers. 10.Câu 10: We need to determine properties related to H being an intersection point for altitudes in triangle ABC based on an image provided. 11.Câu11 :We have G as centroid so GD/AG=$\frac13.$ Therefore, following these steps will lead us to all final given answers: Câu 1: B Câu 2: D Câu 3: A Câu 4: C Câu 5: D Câu 6: A Câu7:-1 Cau8 :5 Cau9:['A', 'C']