Math problems for the first year of junior high school! Urgent! Heavy money

Simplify: EAD = EAC - CAD

EAC = BAC2=90-(B+C)2 AE score BACCD=90-C right triangle.

ead=90-(∠b+∠c)/2-(90-∠c)(∠c-∠b)/2

Five times a monomial, there is 2+|a|=5, then a=3 or -3; Because (a-3) cannot be equal to zero, a=-3; is a monomial, then there is no addition operation, so (b+2)=0, so b=-2.Substituting a 2-3AB+B 2 gives 9-3*(-3)*(2)+4=-5

No, a monomial is a formula that only multiplies and divides, and does not add or subtract.

Because it is a 5-time monomial, 2 + absolute value a=5, so a = plus or minus 3, because a-3 is not 0So a=-3And because it is a monomial, so b+2=0, so b=-2So the value is -5

It's not a mononomial, it's a binomial.

Using the overall substitution method, first the formula is reduced to x+y and xy, 4 and 3 are brought in, and finally the evaluation is: solution: original formula = x+y=4

xy=-32x-y)-(3y+xy-1)

2x-y+3y-xy+1

2x+2y-xy+1

2(x+y)-xy+1

1-3=-2

There are 50 odd numbers from 1 to 99, and there are 25 pairs.

The answer is (-2) x 25 = -50

-50 If it is one to one hundred, then it is a hundred numbers, and now it is an odd number, so it is 50 numbers, and every two numbers form a -2 combination, so it is 25 pairs, so -2*25

I just answered a similar question the other day: no permutations and combinations (junior high school students don't learn) or observation, observation can be seen: this number is listed as an odd number of items within 100, a total of 50, and the sum of each two is a 2, then there are 25 2s, and the answer is 50

(1) 9*27

Answer: 1 243

3x+2y)+(4x+3y) where x=5, y+3 solution: the original formula = 3x+2y+4x+3y=7x+5y, when x=5, y=3.

Original = 5*7+(-3)*5+20

2.(5a 2-3b 2) + (a 2 + b 2) - (5a 2 + 3b 2), where a = -1 and b = 1

5a^2-3b^2+a^2+b^2-5a^2-3b^2=a^2-5b^2

4b-1)-2ab 2 -2 where a = -2, b = 2 = 2a 2b + 2ab 2-2a 2b + 2-2ab 2-2 = 0

One: 365. The middle difference is added by the first square, square, and three powers of 3.

II:13; -24。(Bring it in.)

III:52; is +2, b is -3, and c is *4. Four: Win answer: profit yuan.

Five: 25*20-3-2*

Yuan. If you keep the whole number, the answer is 1206.

Among them, 25 * 20 is the total weight, and the standard is less -, more +, so the chain understands?

Six: We hate number sequences, so we can't help you.