Answer:
1. quadratic
2. cubic
3. linear
4. constant
Step-by-step explanation:
The average of a set of data is equal to the sum of the values divided by the number of data present. So, if we have three numbers, the average would be:
let x, y and z represent the three numbers
average = x + y + z / 3 = 45
Two number are equal in value, so let x = y. Substituting the value to the expression of average,
45 = x + x + z / 3
45 = 2x + z / 3
It said that the last number is 89 so z is equal to 89.
45 = 2x + 89 / 3
135 = 2x + 89
46 = 2x
x = 23
Therefore, the two numbers are both 23.
To find the intersection points, you take x^2 - 4x + 9 = -2x + 17
This gives x^2 - 2x - 8 = 0,
which factorises to (x - 4)(x + 2) = 0, giving the solutions x = 4 or x = -2
From the graph, we can see that x is positive, meaning x = 4, so a = 4.
Substituting x = 4 into y = -2x + 17, we get y = -2(4) + 17 = 9, so b = 9.
a + b = 4 + 9 = 13. The answer is B.
