My father is 40 years old and my son is 12 years old. How many years later, my father is twice as old as my son

My father is 40 years old and my son is 12 years old. How many years later, my father is twice as old as my son

This problem can be solved by equation
Suppose that after X years, the father's age is twice that of his son
40+X=2*（12+X）
40+X=24+2X
X=16
A: 16 years later, the father's age is twice that of his son

Given the first-order function y = KX + B, when 0 ≤ x ≤ 2, the value range of the corresponding function value y is - 4 ≤ y ≤ 8, then the value of KB is______ ．

(1) When k ＞ 0, y increases with the increase of X, that is, the first-order function is an increasing function; when x = 0, y = - 4; when x = 2, y = 8, substituting into the analytic formula of first-order function y = KX + B, we get b = − 42K + B = 8, the solution is k = 6B = − 4, KB = 6 × (- 4) = - 24; (2) when k ＜ 0, y decreases with the increase of X, that is, the first-order function is a decreasing function; when x = 0, y = 8, when x = 2, y = - 4, substituting The analytic formula of a function y = KX + B is: B = 82k + B = − 4, the solution is k = − 6B = 8, ｜ KB = - 6 × 8 = - 48. So the value of KB is - 24 or - 48. So the answer is - 24 or - 48

My son is 13 years old. My father is 40 years old. Is there a year when my father is four times as old as his son?

In the year of X, the father's age is exactly four times of his son's. The answer is: x = - 4. Four years ago, the father's age was exactly four times of his son's

Function f (x) = - 2x ^ 2 + 6x (- 2)

f(X)=-2x^2+6x=-2(x-3/2)^2+9/2
When x = - 2, f (x) = - 8-12 = - 20
When x = 2, f (x) = - 8 + 12 = 4
Function f (x) = - 2x ^ 2 + 6x (- 2)

My son is 13 years old. My father is 40 years old. Is there a year when my father is four times as old as his son?

In the year of X, the father's age is exactly four times of his son's. The answer is: x = - 4. Four years ago, the father's age was exactly four times of his son's

0 ≤ x ≤ 2, f (x) = 2x ^ 2-6x + 1

F(x)=2x^2-6x+1
=2(x-3/2)^2-7/2
X = 3 / 2, minimum - 3.5
X = 0, maximum 1

My son is 13 years old. My father is 40 years old. Is there a year when my father is four times as old as his son?

In the year of X, the father's age is exactly four times of his son's. The answer is: x = - 4. Four years ago, the father's age was exactly four times of his son's

Function f (x) = - 2x ^ 2 + 6x (- 2)

Draw the parabola of quadratic function, take - 2 on X axis

1. My father is 39 years old and my son is 11 years old. How many years later will my father be three times as old as twelve characters

A is the age of the father, B is the age of the son, and X is the age of the father three times that of the son several years later
A=39,B=11
A+X=(B+X)*3
39+X=(11+X)*3
X=3
Three years later, the father was three times as old as his son

Find the function f (x) = 2x ^ 2-6x + C, X belongs to the range of [1,3]

f(x) =2x²-6x+c
= 2(x²-3x) +c
= 2(x-3/2)² - 2*(3/2)² +c
= 2(x-3/2)² +c - 9/2
Because x belongs to [1,3]
So x-3 / 2 belongs to [- 1 / 2,1 / 2]
So (x-3 / 2) &# 178; belongs to [0,1 / 4]
SO 2 (x-3 / 2) &# 178; belongs to [0,1 / 2]
So f (x) = 2 (x-3 / 2) &# 178; + C-9 / 2 belongs to [0 + C-9 / 2,1 / 2 + C-9 / 2]
So the range of function f (x) is [c-4.5, C-4]