Answer (B) 2/3
Explanation: the multiplicative rate is the ratio of the values y(k)/y(k+1) (with k being the index). This ratio must be the same for the function to be exponential. We can take y(2)/y(1) = 4/6 = 2/3.
We can use 2/3 to verify the remaining entries:
x=3: 4*2/3 = 8/3 = y(3)
x=4: (8/3)*(2/3)=16/9=y(3)
To find the pre image you need to back track on the image. To get to the image you used (x-6,y+8). Now you need to use the exact opposite to get back to the pre image. For this you would change the signs to look like (x+6,y-8). Now we just apply this to (-4,1).
(-4+6,1-8)
(2,-7) should be the pre image point.
The second question is the first choice
The answer is 5x because when you do the math 12 subtracted by 7 equals 5 then you add the x at the end.
Let's solve your system by substitution.
2x−2y=−4;2x+y=11
Rewrite equations:
2x+y=11;2x−2y=−4
Step: Solve2x+y=11for y:
2x+y=11
2x+y+−2x=11+−2x(Add -2x to both sides)
y=−2x+11
Step: Substitute−2x+11foryin2x−2y=−4:
2x−2y=−4
2x−2(−2x+11)=−4
6x−22=−4(Simplify both sides of the equation)
6x−22+22=−4+22(Add 22 to both sides)
6x=18
6x/6 = 18/6
(Divide both sides by 6)
x=3
Step: Substitute3forxiny=−2x+11:
y=−2x+11
y=(−2)(3)+11
y=5(Simplify both sides of the equation)
Answer:
x=3 and y=5