Given the quadratic power of a + AB = - 3, the quadratic power of AB + B = 7, try to find the quadratic power of a - the quadratic power of B

Given the quadratic power of a + AB = - 3, the quadratic power of AB + B = 7, try to find the quadratic power of a - the quadratic power of B

The second power of a + AB = - 3
The second power of AB + B = 7
The upper formula minus the lower formula
The second power of A-B = - 3-7 = - 10

Given that P (a) = 0.4, P (b) = 0.3, P (AB) = 0.18, try to find: P (A / b), P (a + b), P (non AB), P (non A, non B), P (non A + b)

P(A/B)=P(AB)/P(B)=0.18/0.3=0.6
P(A+B)=P(A)+P(B)-P(AB)=0.7-0.18=0.52
P (non AB) = P (b) - P (AB) = 0.3-0.18 = 0.12
P (non-A, non-B) = 1-p (a) - P (b) + P (AB) = 1-0.4-0.3 + 0.18 = 0.48
P (non-A + b) = 1-p (a) = 0.6

It is known that, as shown in figure 18-7, in △ ABC, ∠ C = 60 °, ab = 13, AC = 8, ad is the height on the edge of BC, and the length of BC is obtained

Because angle c = 60, ad is high
So CAD = 30
So CD = 0.5ac = 4
AD^+CD^=AC^>>>AD^=8^-4^(1)
AD^+DB^=AB^>>>DB^=13^-AD^(2)
(1) Substituting (2) DB = 11
BC=AD+DB=15

1 2 3 4 5 6 7 8 9 10 11 each number is connected with an addition and subtraction sign to make the result equal to 1
If not, you can use multiplication and division

12-3-4+5-6-7-8-9+10+11

1 2 3 4 5 6 7 8 9 can only use the plus and minus sign, how can it be equal to 10
That is, use +, - before some of the nine numbers to make 10

If you want to add and subtract nine numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 to get 10, first consider adding up all the nine numbers. The sum of the nine numbers 45 and 45 is odd. If you want to change some of these plus signs to minus signs, you need to subtract 35 from 45 to get 10 and 35 is odd. If you change the sign of a number, you need to subtract an even number. The sum of several even numbers cannot get 35, so this problem is wrong

A number minus 10% is equal to 2 / 3 of 234

This number is 234 × 2 / 3 (1-10%) = 173 and 1 / 3

1 / 2 of a number is 20%, equal to 10. What's the number?

Let this be X,
According to the meaning of the title, X * 1 / 2 * 20% = 10,
1 x = 0,
We get x = 100
So the number is 100

Four out of five times a number equals three out of ten

3 / 10 △ 4 / 5 = 3 / 8

Three fifths of a number is three fourths. What's one tenth of a number?

3 / 4 △ 3 / 5 x 1 / 10
=3 / 4 x 3 / 5 x 10 / 1
=5 / 4 x 1 / 10
=One in eight

2% of a number is more than 20% of 90. What's the number?

90×﹙1＋20％﹚÷2/3＝162.