The charges for the usage of per m³ of water and per kWh of electricity are $1.94 and 26 cents respectively. In May, Mr Kumar used x m³ of water and y kWh of electricity and his bill came to $272.10. In June, his bill came to $202.60 for the usage of (x-5) m³ of water and (3y - 1950) kWh of electricity. Form two equations in x and y and solve these two equations to find the total cost of using (x+8) m³ of water and (2y-725) kWh of electricity.

help

Bottle A contains 15% syrup. Bottle B contains 40% syrup. When these 2 bottles of syrup are mixed, the syrup content is 30% and the total volume is 600ml. How much syrup is in the bottle A at first?

Let ABCD be a trapezoid with bases AB, CD and O be the intersection of AC and BD. If the areas of triangle OAB, triangle OCD are 16cm², 40cm²respectively and M is the midpoint of BD, then the area of the triangle AMD is .........cm².

Suppose that the polynomial f(x) = x⁵ - x⁴ - 4x³ + 2x² + 4x + 1 has 5 solutions x₁; x₂; x₃; x₄; x₅. The other polynomial k(x) = x² - 4.
Find the value of P = k(x₁) x k(x₂) x k(x₃) x k(x₄) x k(x₅)

1.If 2x-y=5 then the value of M=\(\left(x+2y-3\right)^2-\left(6x+2y\right)\left(x+2y-3\right)+9x^2+6xy\)

\(+y^2\)

2.The free coefficient in the following poly nomaial: \(\left(2x-2\right)\left(x+1\right)\left(7-x^2\right)is:\)

3.The greatest integer number x such that \(\frac{2x-1}{x-3}-1< 0\) is:

4.How many of the integer n such that satisfy the inequality \(\left(n-3\right)^2-\left(n-4\right)\left(n+4\right)< =43\) are less than 3?

5.The opposite fraction of \(\frac{x-2}{7-x}\) is:

Câu 1 The function mm is defined on the real numbers by m(k) = \dfrac{k+2}{k+8}m(k)= k+8 k+2 ​ . What is the value of 10\times m(2)10×m(2)? Answer: Câu 2 The function ff is defined on the real numbers by f(x)= ax-3f(x)=ax−3. What is the value of a if f(3)=9f(3)=9? Answer: Câu 3 The function ff is defined on the real numbers by f(x)= 2x+a-3f(x)=2x+a−3. What is the value of a if f(-5)=11f(−5)=11? Answer: Câu 4 The function ff is defined on the real numbers by f(x) = 2 + x-x^2f(x)=2+x−x 2 . What is the value of f(-3)f(−3)? Answer: Câu 5 Given a real number aa and a function ff is defined on the real numbers by f(x)=-6\times|3x|-4f(x)=−6×∣3x∣−4. Compare: f(a)f(a) f(-a)f(−a) Câu 6 There are ordered pairs (x;y)(x;y) where xx and yy are integers such that \dfrac{5}{x}+\dfrac{y}{4}=\dfrac{1}{8} x 5 ​ + 4 y ​ = 8 1 ​ Câu 7 Given a negative number kk and a function ff is defined on the real numbers by f(x)=\dfrac{6}{13}xf(x)= 13 6 ​ x. Compare: f(k)f(k) f(-k)f(−k) Câu 8 Given a positive number kk and a function ff is defined on the real numbers by f(x)=\dfrac{-3}{4}x+4f(x)= 4 −3 ​ x+4. Compare: f(k)f(k) f(-k)f(−k). Câu 9 A=(1+2+3+\ldots+90) \times(12 \times34-6 \times 68):(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6})=A=(1+2+3+…+90)×(12×34−6×68):( 3 1 ​ + 4 1 ​ + 5 1 ​ + 6 1 ​ )= Câu 10 Given that \dfrac{2x+y+z+t}{x}=\dfrac{x+2y+z+t}{y}=\dfrac{x+y+2z+t}{z}=\dfrac{x+y+z+2t}{t} x 2x+y+z+t ​ = y x+2y+z+t ​ = z x+y+2z+t ​ = t x+y+z+2t ​ . The negative value of \dfrac{x+y}{z+t}+\dfrac{y+z}{t+x}+\dfrac{z+t}{x+y}+\dfrac{t+x}{y+z} z+t x+y ​ + t+x y+z ​ + x+y z+t ​ + y+z t+x ​ is