Junior high school math problems, urgent!! Bounty 10

When the denominator is equal to 0, the fractional formula doesn't make sense, so.

1) But the equation ≠-2 and x≠-3 makes sense.

2) When x=-2 or x=-3, the fraction is meaningless.

3) The value of the equation is 0 when x=4

Please note the words "and" and "or", which are the words that are used in the test.

When x = -2 or x = -3, the fraction is meaningless, and when x is not equal to -2 and not equal to -3, the fraction is meaningful. When x=4, the value of the fraction is zero.

When x-4<>0, i.e., x is not equal to 4, the fraction makes sense;

When x-4=0, i.e., x=4, the fraction is meaningless; When x is not equal to 4 and (x+2)(x+3) = 0, i.e., x = -2 or -3, the value of the fraction is 0. When you learn fractions in the second year of junior high school, you'll understand.,Anyway, how can I take such a question in the first year of junior high school = =.

1) Meaningful: x is not equal to -2 or -3

2) Meaningless: x is equal to -2 or -3

3) The fractional value is 0: x=4

x=-2 or x=-3 is meaningless.

x""-2 and x""-3 make sense.

x=4 The fractional value is 0

Not equal. Note: Meaningless is or, and when meaningful, it is and.

。。Belch... It's the opposite of what I'm used to...

This triangle is half of the square with a diagonal, and you can think of the rest.

Isosceles right triangle. The vertical foot of the isosceles triangle is the midpoint of the base.

It is an isosceles right-angled triangle ......

Set the speed x. in windless conditions

x+24) * because distance between two fields = speed * time].

x=552km/h

Two distances = (552-24) * 6 = 3168km thank you

Let the distance be x km.

x x = 3168 km.

Let the aircraft speed be v(

kilometers per hour).

The velocity when flying over (v+24), the distance is (v+24) * the velocity (v-24) when flying back, and the distance is (v-24)*6, both are equal, and v = 552 km h.

So the distance is (v+24)*km.

Let the velocity of A be x and the velocity of B be y

Then 2 3x+4 3x)+5 3y=36 has 1 to get x+y=20

So x=20-y is substituted for 2

There are 2 to get 6x+5y=108

So 6 (20-y) + 5y = 108

The solution is y=12 and x=8

So the speed of A is 8km h

B's velocity is 12kmh

Solution: Let the velocity of A be x km/h, and the velocity of B be ykm/h (3 2+3 2)x+(3 2)y=36

The solution is x=4 and y=16

A: A is traveling at a speed of 4 km/h, and B is traveling at a speed of 16km/h.

Let the velocity of A be x km h, B y km h, 2x+4 3y=36, and the solution is x=14, y=6

You search for this question above.

Is it a straight line? If yes, it's 87°55 [That's it... If you have a flat angle, it's 180].

do you understand?

3=180°- 1- 2=180°-27°30 -65°15 =87°15 The 180° is because the three of them form a flat angle.

1. a=-2, b=3, so a+b=1

2. a=3,b=4(-3,-4 2,6 -2,-6 1,12 -1,-12) so a+b=7(-7 8 -8 13 -13).

3. a=0, b=1 or -1 |a-b|=1 (a=1 or -1, b=0 the answer is the same, it is also 1).

4. Original = I don't know if this question is wrong, my answer is to change the last 82 to 28) 5, I don't know (|c|+c) whether it is a typo.

If you make a mistake, c may be negative (|c|+c is 0, and |a|／a，|b|b is either 1 or -1 and does not satisfy the equation).

Or positive (a, b, one positive and one negative can satisfy the equation to hold) so a, b, c, two positive and one negative, the final result is -1 If you make a mistake, the result is also a, b, c two positive and one negative, the result is also -1, but the process is different. Layer.

1、a+2=o a=-2 b-3=0 b=3 a+b=1

2. When a=3, b=4 (a=-3, b=-4 a=2, b=6 a= -2, b=-6 a=1, b=12 a=-1, b=-12) so a+b=7 (or -7 or 8 or -8 or 13 or -13) "as opposed to the number of brackets above".