It is proved that y = - x + 1 is a decreasing function in R

It is proved that y = - x + 1 is a decreasing function in R

prove:
Let y = f (x) = - x + 1, X1 > X2, x2-x1

If △ ABC is known, ab = 2cm, AC = 1cm and angular bisector ad = 1cm, then the area of triangle ABC is

Let ∠ bad = α, and make the vertical lines de and DF of AB and AC respectively through D, then de = DF = sin α, AE = AF = cos α. According to the "cosine theorem", we can know that BD ^ 2 = 5-4cos α, CD ^ 2 = 2-2cos α, and the area of triangle abd is sin α, and the area of triangle ACD is 0.5sin α

The greatest common factor of the two numbers is 9, and the least common multiple is 243______ And______ ．

9 = 3 × 3243 = 3 × 3 × 3 × 3, these two numbers are 9 and 243, so the answer is: 9243

If the corresponding sides of two similar triangles are 3cm and 5cm respectively, then the perimeter ratio of the two similar triangles is the area ratio
RT
process
、、、

The similarity ratio was 3:5
So the perimeter ratio is 3:5
The area ratio is 9:25

The greatest common divisor of two positive integers is 6, and the least common multiple is 90. There are several pairs of large numbers composed of two positive integers satisfying the condition
By the way, what is number right!

90/6=15
15=1*15=3*5
6*1=6
6*15=90
6*3=18
6*5=30
So there are two pairs that meet the conditions: 90, 6 and 30, 18

Given that the line l1:2x-y + 3 = 0, the line L2 and L1 are symmetric with respect to the line y = 0, and the line L3 ⊥ L2, then what is the slope of L3?
A.1/2 B.-1/2 C.-2 D.2

Line L1: 2x-y + 3 = 0, line L2 and line L1 are symmetric about line y = 0, that is, about line X axis,
So the line l2:2x + y + 3 = 0, slope: - 2,
Line L3 ⊥ L2, so the slope of line L3 is 1 / 2
Choose a

One and a half days or one and a half days
One day and a half

One and a half days = one day and a half
1.5 one point five

If the vertex of the parabola y = - x ^ - 2x + m is on the X axis, what is m

If the vertex of the parabola y = - x ^ - 2x + m is on the X axis, there is only one intersection point between the parabola and the X axis, that is, the equation - x ^ - 2x + M = 0 has two equal real roots, so the discriminant 4 + 4m = 0, so m = - 1

To the x power of 2 = 3 to the X + 3 power of 2

X + 3 power of 2 = x power of 2 times 3 power of 2 = 3 times 8 = 24

Given that the distance from a point m to one of its focal points on hyperbola x ^ 2 / 16-y ^ 2 / 20 = 1 is equal to 6, then the distance from point m to another focal point is?

The first definition: the absolute value of the difference between the distance from a point on a hyperbola to two focal points = 2A
So: | 6-D | = 8,
D = 14