When x is the value, the value of the polynomial 3x2 + 4x-3 is 1 larger than that of 2x2 + 3x-1

When x is the value, the value of the polynomial 3x2 + 4x-3 is 1 larger than that of 2x2 + 3x-1

From the meaning of the title, we can get 3x-178; + 4x-3 = 2x-178; + 3x-1 + 1
The result is 3x & # 178; - 2x & # 178; + 4x-3x-3 + 1-1 = 0
By combining the similar terms, we get X & # 178; + x-3 = 0
From the root formula, x = [- 1 + √ 1 & # 178; - 4 × 1 × (- 3)] / (2 × 1 × 1) or x = [- 1 - √ 1 & # 178; - 4 × 1 × (- 3)] / (2 × 1 × 1)
That is, x = (- 1 + √ 13) / 2 or (- 1 - √ 13) / 2
(just search the Internet for the root formula of quadratic equation of one variable. It's also available in mathematics books.)

Simplify (x4 + X3 + 2x2-3x + 2) - (AX2)_ 3x2+bx+1)

(x4+x3+2x2-3x+2)-(ax2_ 3x2+bx+1)
=x^4+x^3-(a-5)x^2-(b+3)x+1

If x = 2, the value of the algebraic expression ax3-2 is 3. If x = - 2, the value of the algebraic expression ax3-2 is 3______ ．

When x = 2, ax3-2 = 38a = 5A = 58; when x = - 2, a = 58, generation ax3-2 = 58 × (- 8) - 2 = - 5-2 = - 7; so the answer is: - 7

There are 18 girls in a class, accounting for two fifths of the total number of students in the class. How many students are there in the class? How many students are there?

Solution 1: according to the meaning of the question: because there are 18 girls in a class, accounting for two fifths of the total number of students in the class! So: the total number of students in the class is: 18 (2 / 5) = 45 (people), so: the number of boys is: 45 - 18 = 27 (people), so: the number of boys in the class is: 27 (2 / 5) = 3 / 5

Simple operation of 45.6 * 6.7 + 4.56 * 31 + 0.46 * 20

45.6*6.7+4.56*31+0.456*20
=45.6*6.7+45.6*3.1+45.6*0.2
=45.6*（6.7+3.1+0.2）
=45.6*10
=456

There are three schools: school a, School B and school C. one half of the number of school a is equal to one third of the number of School B and one seventh of the number of school C. It is known that school C has more people than school a
How many people are there in the three schools

One half of school a is equal to one seventh of school C,
Then the ratio of school a and school C is (1 / 7): (1 / 2) = 2:7
Number of students in school a
=120÷[（7-2）/2]
=120÷（5/2）
=48 (person)
Number of students in school B
=48*（1/2）÷（1/3）
=24÷（1/3）
=72 (person)
Number of C
=48÷（2/7）
=168 (persons)
The total number of students in a, B and C schools = 48 + 72 + 168 = 288

How to calculate integers, decimals, fractions and percentages

Operation method: 1, easy to use algorithm 2, decimal fraction, simplify 3, according to the operation rules, first calculate the number in brackets, in the order of small brackets, middle brackets, and curly brackets operation rules appendix: integer addition and subtraction calculation method: 1) align the same digits, and then add or subtract the numbers on the same counting unit; 2) which digit is full

The average number of a, B and C is 75. The ratio of a to B is 4:5, and the ratio of a to C is 2:3. Then what are the ratios of a, B and C? Why do we solve this problem?
Why set C to 6x instead of 3x?

Let C be 6x, then a be 4x, and then B be 5x
If C 3x is set, then a is 2x and B is 5x / 2

A is a real number. Compare the absolute value of A-1 with that of a + 2

The absolute value of A-1 and the absolute value of a + 2 are the distances from a to - 2 and 1 on the number axis. Drawing can clearly draw a conclusion
a> At - 1 / 2, la-1l

When a number is increased by 60%, it is 5 / 3 times of 120,

120*5/3 = 200
200/(1+0.6) = 125