Answer: option d.
Step-by-step explanation:
If <em>y </em>varies directly as <em>x</em> and <em>z</em>, the form of the equation is:

Where<em> k</em> is the constant of variation.
If y=4 when x=6 and z=1 then substitute these values into the expression and solve for <em>k:</em>

<em> </em>Substitute the value of <em>k</em> into the expression. Then, the equation is:

To find the value of <em>y </em>when x=7 and z=4, you must substute these values into the equation. Therefore you obtain:


<em> </em>
Answer: Gas
Step-by-step explanation: This is the only matter that can be raised form the lakes and oceans
Answer:
<h2>(f + g)(x) = x² + 3x - 5</h2>
Step-by-step explanation:

Answer:
a) (i)
, (ii)
, (iii)
, (iv)
, (v)
, (vi)
, (vii)
, (viii)
; b)
; c) The equation of the tangent line to curve at P (7, -2) is
.
Step-by-step explanation:
a) The slope of the secant line PQ is represented by the following definition of slope:

(i)
:




(ii) 




(iii) 




(iv) 




(v) 




(vi) 




(vii) 




(viii) 




b) The slope at P (7,-2) can be estimated by using the following average:



The slope of the tangent line to the curve at P(7, -2) is 2.
c) The equation of the tangent line is a first-order polynomial with the following characteristics:

Where:
- Independent variable.
- Depedent variable.
- Slope.
- x-Intercept.
The slope was found in point (b) (m = 2). Besides, the point of tangency (7,-2) is known and value of x-Intercept can be obtained after clearing the respective variable:



The equation of the tangent line to curve at P (7, -2) is
.