We need to work out the formula A total of 156 yuan will be paid for 3kg pear and 4kg apple. It is known that 5kg pear = 2kg apple, so the price of pear and apple can be calculated

We need to work out the formula A total of 156 yuan will be paid for 3kg pear and 4kg apple. It is known that 5kg pear = 2kg apple, so the price of pear and apple can be calculated

Pear 156 (5 × 2 + 3)
=156÷13
=12 yuan
Apple 12 × 5 △ 2
=60÷2
=30 yuan

Give 3 kg pear to 10 children on average, and each child gets ()% of 3 kg pear, which can also be regarded as ()% of 1 kg pear
10000 yuan is deposited in the bank for one year. After maturity, the principal and after tax interest of 10342 yuan are recovered. The recovered principal is () yuan and after tax interest is () yuan. The annual interest rate is ()

10% 30%
10000 342 3.42%

2 / 3 of a number is 4 less than 1 / 3 of 30. What's the number?

Let this number be x, then 2x / 3 = 30 * 1 / 3-4; 2x / 3 = 6; then x = 9; hope to help you,

If a root of the equation x ^ 2-5x + 2 = 0 is a, what is the value of a + 2 / a?

One root of the equation x ^ 2-5x + 2 = 0 is a,
So, a ^ 2-5A + 2 = 0
Divide both sides by a (obviously a is not equal to 0)
a - 5 + 2/a = 0
a + 2/a = 5

If a is a root of the equation x ^ 2-5x + 1 = 0, find the value of a + 1 / A

A is a root of the equation x ^ 2-5x + 1 = 0
a^2-5a+1=0
a^2+1=5a
a+1/a=(a^2+1)/a
=5a/a
=5

If the constant term of equation (m-1) XX + 5x + mm-3m + 2 = 0 is 0, then the value of M is equal to?

That is mm-3m + 2 = 0, solve the quadratic equation to get m = 2 or M = 1 (cross phase multiplication)
Because it's a quadratic equation about X
So m is not equal to 1
So m = 2

If a is a root of the equation x ^ 2-5x + 1 + 0, find the value of a ^ 2 + a

The equation can be written as x ^ 2 + x = 6x-1 to draw two images, and the two values obtained are the ordinates of two intersection points

Given the equation (M + 1) x ^ 2 + (1-2x) M = 2 about X, what is the value of M
1. The equation has two unequal real roots
2. The equation has two equal real roots
3. The equation has no real root

(m+1)x^2+(1-2x)m=2
(m+1)^2-2mx+m-2=0
4mx^2-4*(m+1)（m-2）＞0
m＞-2
4m^2-4*(m+1)（m-2）=0
m=-2
4m^2-4*(m+1)（m-2）＜0
m＜-2

A problem about the discriminant of the root of equation
It is known that a, B and C are the three sides of the triangle ABC. Try to judge the root of the equation (B-C) X2 (square) - 2aX + B-C = 0 (b not = 0) about X

The discriminant is 4A ^ 2-4 (B-C) ^ 2 = 4 (a-b + C) (a + B-C);
According to the triangle trilateral relationship, A-B + C = a + C-B > 0;
a+b-c=a+b-c>0;
So the discriminant is greater than 0; there are two different real roots

How to use the discriminant of the root of quartic equation with one variable?
△1=c^2-3bd+12ae
△2=2c^3-9bcd+27b^2*e+27ad^2-72ace
The above two discriminant are known
How to use them to judge the root of quartic equation?

Look at page 56 of the Handbook of advanced mathematics