Answer:
the cost of one hot chocolate is $2.
Step-by-step explanation:
Let x be the hot chocolate cost and y be the newspaper cost.
Given:
A newspaper and three hot chocolates cost $7
So, the equation is
--------(1)
Two newspapers and two hot chocolates cost $6
So, the second equation is.
---------(2)
Find one hot chocolate cost?
Solve equation 1 for y.


Put y value in equation 2





negative sign is cancelled both side.


Therefore, the cost of one hot chocolate is $2.
Answer with Step-by-step explanation:
The given differential equation is

Now the above differential equation can be re-written as

Checking for exactness we should have



As we see that the 2 values are equal thus we conclude that the given differential equation is exact
The solution of exact differential equation is given by

The value of
can be obtained by differentiating u(x,y) partially with respect to 'y' and equating the result with P(x,y)

Answer: c) About 16% of the variation in value of the car is explained by a linear relationship with the age of the car.
e) The correlation coefficient, r, is 0.397.
Step-by-step explanation:
Given that:
Coefficient of determination (r²) between two variables, age of car (x) and value of car (y) = 0.158
Correlation of determination (r²) of 0.158 = (0.158 × 100% = 15.8% of the variation between the two variables can be explained by the regression line). Hence, about 16% of the variation between age and value of car can be explained by the linear relationship.
Coefficient of correlation (r) = sqrt(r²) = sqrt(0.158) = 0.397
Step-by-step explanation:
Root of the function, where y = 0
f(x) = x² + 2x - 1
0 = x² + 2x - 1
x² + 2x - 1 = 0
x² + 2x = 1
x² + 2x + 1 = 1 + 1
(x + 1)² = 2
x + 1 = ±√2
x = -1 ± √2
Roots → x = -1 ± √2