What is the root of the function f(x)=3x^2-21x?
1 answer:
You might be interested in
<h2>Answer:</h2>
BC ≅ 11cm
<h2>Step-by-step explanation:</h2>To accomplish this task, follow these steps:
i. Using your ruler, draw a line AB with length 8cm as shown in Figure 1. This will give AB = 8cm
ii. Remove the ruler and place your protractor at the point A and parallel to line AB as shown in Figure 2. Make a dot at the mark 90° of the protractor (See Figure 2). For accuracy, ensure that the 180° mark of the protractor is on the line AB.
iii. From point A through the dot in (ii) above, use a ruler to draw a line AC of length 8cm as shown in Figure 3. This will give AC = 8cm and will also give angle CAB = 90°
iv. Now join points C and B by drawing a line from point A to C using a ruler as shown in Figure 4.
v. Lastly, measure the length of BC by placing your ruler on line BC as shown in Figure 5. This should give a value of about 11cm.
Therefore the length of BC = 11cm approximately.
<em>NB: All figures are attached to this response. </em>
Answer: fourth option
Explanation:
1) the pair x = 3 f(x) = 0, leads you to probe this:
f(3) = 0 = A [4 ^ (3 - 1) ] + C = 0
=> A [4^2] = - C
A[16] = - C
if A = 1/4
16 / 4 = 4 => C = - 4
That leads you to the function f(x) = [1/4] 4 ^( x - 1) - 4
2) Now you verify the images for that function for all the x-values of the table:
x = 2 => f(2) + [1/4] 4 ^ (2 - 1) - 4 = [1/4] 4 - 4 = 4 / 4 - 4 = 1 - 4 = - 3 => check
x = 3 => f(3) = [1/4] 4^ (3 - 1) - 4 = [1/4] 4^2 - 4 = 16 / 4 - 4 = 4 - 4 = 0 => check
x = 4 -> f(4) = [1/4] 4^ (4-1) - 4 = [1/4] 4^(3) - 4 = (4^3) / 4 - 4 = 4^2 - 4 = 16 - 4 = 12 => check.
Therefore, you have proved that the answer is the fourth option.
Explanation:
1) the pair x = 3 f(x) = 0, leads you to probe this:
f(3) = 0 = A [4 ^ (3 - 1) ] + C = 0
=> A [4^2] = - C
A[16] = - C
if A = 1/4
16 / 4 = 4 => C = - 4
That leads you to the function f(x) = [1/4] 4 ^( x - 1) - 4
2) Now you verify the images for that function for all the x-values of the table:
x = 2 => f(2) + [1/4] 4 ^ (2 - 1) - 4 = [1/4] 4 - 4 = 4 / 4 - 4 = 1 - 4 = - 3 => check
x = 3 => f(3) = [1/4] 4^ (3 - 1) - 4 = [1/4] 4^2 - 4 = 16 / 4 - 4 = 4 - 4 = 0 => check
x = 4 -> f(4) = [1/4] 4^ (4-1) - 4 = [1/4] 4^(3) - 4 = (4^3) / 4 - 4 = 4^2 - 4 = 16 - 4 = 12 => check.
Therefore, you have proved that the answer is the fourth option.