Math problems Good home bounty is best to have a detailed process and the meaning of each step Good

1. Calculate the price first: 1260 (1+20%)=1512 yuan.

Then the price of 10% off now is: 1512 yuan.

So is earned: dollars.

2. Because the total amount of principal and interest = principal + principal annual interest rate period.

So the principal = the total amount of principal and interest (1 + annual interest rate and years) 3, the number of pages on the second day is 20% more than on the first day, so you can find the number of pages on the second day as: 45 (1+20%) = 54 pages.

The next day is a third of the book, so the total number of pages is: 54 1 3 = 162 pages.

If the original price of the microwave oven is x, (1 + 20%) x = 1260, x = 1050 is sold at a nine-percent discount (I guess it should be a typo by the landlord), then ** is 1260 * 90% = 1134

The profit is 1134-1050=84

The principal amount is x, the annual interest rate is i, the term is n years, and the total principal interest is ax+x*i*n=a.

The number of pages read on the second day: 45 * (1 + 20%) = 54, the number of pages of the whole book: 54 divided by 1 3 = 162

Solution: 1 principal + principal multiplied by annual interest rate multiplied by term.

54 divided by 1 3 = 162

1/10 x 4/5

10*1 = 2*4/1 = 10 people = 8 (people) Answer: Aircraft carrier.

No time.

2.Given the unknown, the vegetable plot = 18

One-third = 10 10 * four-fifths = 8 people.

1 30x one-third x four-fifths = 8 (people).

1。Will cost $x per piece of clothing

80 *（100-x）100 =（100 *（1-5％）-x）*（80 100 * 5％* 4）

The solution is: x = 70

Solution judgment ab cd

Proof b= d- e

b+∠e=∠d

and afe is the outer angle of δbef.

afe=∠b+∠e

afe=∠d

ab//cd

and ab parallel cd (equal isotope angles, two lines parallel).

Because the angle afe is equal to the angle e plus the angle b, and the angle d is equal to the angle b plus the angle e, so the angle d is equal to the angle afe, so it is parallel.

Because the angle b plus the angle e is equal to the angle d, and because the angle b plus the angle e is equal to the angle afe, the angle afe is equal to the angle d, so ab is parallel cd. This question examines two knowledge points, one is that the outer angle of a triangle is equal to the sum of the other two inner angles, and the other is the isotopic angle theorem.

Proof: Extend EF to BC to M

aef=∠afe

afe = bfm (equal at equal angles).

aef=∠bfm

ac=ab∠b=∠c

bfm+∠b=∠aef+∠c

In BFM: BMF=180°-(BFM+B) CEM: CME=180°-(AEF+C)BMF= CME

bmf + cme = 180° (definition of ortho complement angle) bmf = cme=90°

i.e. EF BC

I'm glad to solve the above problems for you, I hope it will help you in your studies! 】≤

At point O, set the angle abo=cbo=x, tan(45-x)=eo ob=3 ob; tanx=2 ob, x can be solved, and the liquid skin can be found by sinx=2 ab

A 45-degree angle is a bit of a hassle to use, what have you been learning lately?