Aunt Li bought 2kg eggs and 10kg rice for 88.6 yuan, while Aunt Wang bought the same eggs and rice for 0.5kg Formula

Aunt Li bought 2kg eggs and 10kg rice for 88.6 yuan, while Aunt Wang bought the same eggs and rice for 0.5kg Formula

Your question is not complete. It's easy to do this kind of problem with "elimination method"
2 kg egg + 10 kg rice = 88.6 yuan
0.5kg egg + 5kg rice = 42 yuan
Multiply 2 by 2
1 kg egg + 10 kg rice = 84 yuan
Formula 1-3 is as follows:
1 kg egg = 2.6 yuan, which can be substituted into Formula 1 to get rice
The above is a simple example, this is to lay the foundation for junior high school equation

A barrel of oil weighs 26kg after half use and 8kg after 80% use. How much is the barrel of oil?

If the answer is 60kg, the weight of the barrel will be negative (- 4kg). It is estimated that after 80% is removed, the weight of the barrel will be 8kg. So (26-8) = (0.5-0.5x0.8) x oil weight, and the oil weight will be 45kg

As shown in the figure, in the parallelogram ABCD, ab = 2BC, be is perpendicular to ad, and F is the midpoint of CD. Let ∠ def be α, ∠ EFC = β. Prove β = 3 α
Take the midpoint g of AB, connect FG to be and connect FB
Then ad is parallel to FG, be ⊥ FG
Because G is the midpoint of AB, O is the midpoint of be
It can determine the isosceles triangle Feb, so ∠ EFO = ∠ BFO
Because CF = 0.5cd = CB,
So the quadrilateral bcfg is a diamond, so ∠ GFB = ∠ CFB
So fo and FB are the triad of β, α = ∠ EFO = 1 / 3 β
So β = 3 α. Why is g the midpoint of AB, so o the midpoint of be,

G is the midpoint of ab. let's take the midpoint of ab
G is the midpoint of AB, and O is the midpoint of be

What is the minus seventh power of 10 divided by the minus nineteenth power of 1.6?

Hello 0.00075557862, hope to adopt

Car a and B start from two places at the same time and travel in opposite directions. They meet seven hours later. Car a is 20 kilometers slower than car B every hour. The speed ratio of the two cars is 7:9. Find the distance between the two places

A's speed: 20 ÷ (9-7) / 7 = 70 (km)
Speed of B: 70 × 9 / 7 = 90 (km)
So the distance between the two places: (70 + 90) × 7 = 1120 (km)

If the sides of an isosceles triangle are 5cm and 8cm respectively, its perimeter is______ ．

① When the waist is 5cm and the bottom is 8cm, the circumference of the triangle is 5 + 5 + 8 = 18cm; when the bottom is 5cm and the waist is 8cm, the circumference of the triangle is 5 + 8 + 8 = 21cm

The corresponding points of the number ABC on the number axis are a, B and C respectively. The distance between point B and point C to point a is equal
If ABC ＜ 0, and the value of a + B + C is equal to one of them
Calculate the value of (a + b) & sup2; + C / A + A / b

The distance from B and C to a is the same, ∧ 2A = B + C, ∫ ABC < 0, B < a < C, there are (1) B < 0, a > 0, C > 0, a + B + C = C, ∧ a = - B, (such as B = - 2, a = 2, C = 6) ∧ (a + b) & sup2; + C / A + A / b = 0 + C / A-1 = (2a-b) / A-1 = (2a + a) / A-1 = 3-1 = 2. (2) B < 0, a < 0, C < 0, B + A + C = B, there are a + C = 0, but a + C

1. Xiao Ming lives on the 12th floor. It takes 80 seconds to walk from the 1st floor to the 5th floor. At this speed, how long does it take him to get home?
2. For the clock tower, it takes 12 seconds to ring 4 times at 4 o'clock, so how many seconds does it take to ring 7 hours at 7 o'clock?

5-1 = 4 (floor)
80 △ 4 = 20 (seconds)
12-1 = 11 (floor)
11 × 20 = 220 (SEC)
4-1 = 3
12 △ 3 = 4 (seconds)
7-1 = 6
6 × 4 = 24 (seconds)
Note that there are intervals
Hope it can be adopted!

If the side length of a square is increased by 2 cm, the area of the new square is 36 cm more than that of the original square. What is the area of the original square?

36 divided by 2 = 18
18 times 18 = 324

2 (3-5a) square - 5 (3a-7) (3a + 7)

2 (3-5a) square-5 (3a-7) (3a + 7)
=2（25a²-30a+9）-5(9a²-49)
=50a²-60a+18-45a²+245
=5a²-60a+263