Answer:
1. Multiply (2) by 2 to eliminate the x-terms when adding
2. Multiply (2) by 3 to eliminate the y- term
Step-by-step explanation:
Use this system of equations to answer the questions that follow.
4x-9y = 7
-2x+ 3y= 4
what number would you multiply the second equation by in order to eliminate the x-terms when adding the first equation?
4x-9y = 7 (1)
-2x+ 3y= 4 (2)
Multiply (2) by 2 to eliminate the x-terms when adding the first equation
4x-9y = 7
-4x +6y = 8
Adding the equations
4x + (-4x) -9y + 6y = 7 + 8
4x - 4x - 3y = 15
-3y = 15
y = 15/-3
= -5
what number would you multiply the second equation by in order to eliminate the y- term when adding the second equation?
4x-9y = 7 (1)
-2x+ 3y= 4 (2)
Multiply (2) by 3 to eliminate the y- term
4x - 9y = 7
-6x + 9y = 12
Adding the equations
4x + (-6x) -9y + 9y = 7 + 12
4x - 6x = 19
-2x = 19
x = 19/-2
= -9.5
x = -9.5
Answer:
a) 
b) Wind capacity will pass 600 gigawatts during the year 2018
Step-by-step explanation:
The world wind energy generating capacity can be modeled by the following function

In which W(t) is the wind energy generating capacity in t years after 2014, W(0) is the capacity in 2014 and r is the growth rate, as a decimal.
371 gigawatts by the end of 2014 and has been increasing at a continuous rate of approximately 16.8%.
This means that

(a) Give a formula for W , in gigawatts, as a function of time, t , in years since the end of 2014 . W= gigawatts



(b) When is wind capacity predicted to pass 600 gigawatts? Wind capacity will pass 600 gigawatts during the year?
This is t years after the end of 2014, in which t found when W(t) = 600. So




We have that:

So we apply log to both sides of the equality





It will happen 3.1 years after the end of 2014, so during the year of 2018.
By the binomial theorem,

Each term containing a factor 6 is divisible by 3, since 3 divides 6. The remaining 1 and 2 sum to 3, which is also divisible by 3.