Answer:
c = - 7
Step-by-step explanation:
the standard form of a quadratic equation is
ax² + bx + c = 0 : a ≠ 0
x² + 4x - 7 = 0 is in standard form
By comparison of the coefficients of the terms, c = - 7
Answer and Step-by-step explanation:
Polynomial models are an excellent implementation for determining which input element reaction and their direction. These are also the most common models used for the scanning of designed experiments. It defines as:
Z = a0 + a1x1 + a2x2 + a11x12 + a22x22+ a12x1x2 + Є
It is a quadratic (second-order) polynomial model for two variables.
The single x terms are the main effect. The squared terms are quadratic effects. These are used to model curvature in the response surface. The product terms are used to model the interaction between explanatory variables where Є is an unobserved random error.
A polynomial term, quadratic or cubic, turns the linear regression model into a curve. Because x is squared or cubed, but the beta coefficient is a linear model.
In general, we can model the expected value of y as nth order polynomial, the general polynomial model is:
Y = B0 + B1x1 + B2x2 + B3x3 + … +
These models are all linear since the function is linear in terms of the new perimeter. Therefore least-squares analysis, polynomial regression can be addressed entirely using multiple regression
She should invest $30000 in the 9% fund and $10000 in the 13% fund.
<u><em>Explanation</em></u>
Suppose, the amount of investment at 9% rate is 
dollar.
As the total amount of investment is $40000 , so the investment at 13% rate will be: 
So, the amount of earnings per year from 9% fund 
dollar
and the amount of earnings per year from 13% fund 
dollar.
Given that, the <u>total earnings per year is $4000</u>. So the equation will be......
So, the amount of investment at 9% fund is $30000 and the amount of investment at 13% fund = ($40000- $30000)= $10000
