4x-3y=17 y=7-5x

4x-3y=17 y=7-5x

4x-3y=17 a
y=7-5x b
Substituting B into a leads to
4x-21+15x=17
19x=38
X=2
So y = 7-5 * 2 = - 3
So x = 2, y = - 3
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Substituting (2) into (1) leads to
4x-21+15x=17
19x=38
X=2
Substituting x = 2 into (2) yields
y=-3
∴x=2
y=-3
The best way to solve this kind of problem is to add and subtract. That's to make the coefficients of X and y the same and then add and subtract them. The problem is to multiply the two equations by three and add them up. 4X=17+21-15X 19X=38 X=2。 Y=-3。
4x-3y=17 （1
5x+y=7
15x+3y=21 (2
（1+(2
19x=38
X=2
y=7-5x=7-10=-3
So,
X=2
y=-3
It is obviously a system of linear equations of two variables
4x-3y=17 (1)
y=7-5x (2)
Substituting (1) into (2)
4x-3 (7-5x) = 17
The solution is x = 2
∵x=2
The equation: - 3Y = 17-8 is obtained
∴y=-3
I did it by myself. I didn't see the answer below!!! Manual typing!!!
The solution set of inequality ax & # 178; + 5x + C > 0 is {x| 1 / 3
That is, 1 / 3 and 1 / 2 are the following of the equation AX & # 178; + 5x + C = 0
So 1 / 3 + 1 / 2 = - 5 / A
1/3*1/2=c/a
So a = - 6
c=-1
The solution set of inequality 2 & nbsp; x2 − 5x + 5 > 12 is______ .
Because the exponential function y = 2x is an increasing function, 2 & nbsp; x2 − 5x + 5 ＞ 12 is changed into: x2-5x + 5 ＞ - 1, that is, x2-5x + 6 ＞ 0, the solution is x ＜ 2 or X ＞ 3, so the solution set of inequality is: {x | x ＜ 2 or X ＞ 3}, so the answer is: {x | x ＜ 2 or X ＞ 3}
It is known that the polynomial K (the square of x) - 6xy-8 (the square of Y) can be decomposed into (2mx + 2Y) * (x-4y)
(2MX+2Y)(X-4Y)
=2mx^2-8mxy+2xy-8y^2
=2mx^2-(8m-2)xy-8y^2
=kx^2-6xy-8y^2
One by one: k = 2m, 6 = 8m-2
The solution is: M = 1, k = 2
The following expansion: 2m (the square of x) - 8mxy + 2xy-8 (the square of Y), so m = 1, k = 2
dfgdfg
Mathematical expression: ① - 5
All inequalities have unequal signs
So there are some inequalities: ①, ②, ⑤, ⑥
1、2、5、6
Three is the equation and four is the equation
The inequalities are: 2; 5; 6
②3y-6
8y-1=4y² 】
The solution of 13-4x square > 0
13-4x²＞0
4x²＜13
x²＜13/4
-√13/2＜x＜√13/2
(1/x-4+1/x+4)÷2/x²-16
The addition, subtraction, multiplication and division of fractions
=(x+4+x-4)/(x+4)(x-4) ×(x+4)(x-4)/2
=2x/(x+4)(x-4)×(x+4)(x-4)/2
=x
=[ (x+4)+(x-4) ] / (x^2-16) * (x^2-16)/2
=2x/2
=X question: (1 / x-4 + 1 / x + 4) △ 2 / X & # 178; - 16
Let me show you. Why do I get x (x-4) / x + 4
If 2Y = 3x + Z, is the square of the polynomial 9x-4y + 4yz-z fixed
If 2Y = 3x + Z, is the square of polynomial 9x-4y + 4yz-z a constant
2y=3x+z;
=>2y-z=3x
=>The square of (2y-z) = 9x square
=>Square of 9x - 4Y + 4yz-z square = 0
Given x > 0, Y > 0, x + 2Y + 2XY = 8, then the minimum value of X + 2Y is ()
A. 3B. 4C. 92D. 112
This paper studies the basic inequality x + 2Y = 8-x · (2Y) ≥ 8 - (x + 2Y2) 2, and concludes that (x + 2Y) 2 + 4 (x + 2Y) - 32 ≥ 0, that is, (x + 2y-4) (x + 2Y + 8) ≥ 0, and X + 2Y > 0, so x + 2Y ≥ 4, so B is chosen