If 3x = 4, 9y = 7, then 3x-2y=

If 3x = 4, 9y = 7, then 3x-2y=

If 3x = 4, 9y = 7, then 3x-2y=
9y=7 y=7/9 2y=14/9
3x-2y=4-14/9=22/9
Solving equations: 2x + 5Y = 16, 5x + 2Y = 19
Solving equations: 2x + 5Y = 16, 5x + 2Y = 19
Conclusion 1: x + y = 5 (2x + 5Y) - (5x + 2Y) = 16-19 (2x-5x) + (5y-2y) = - 33y-3x = - 33 (Y-X) = - 3y-x = - 1 conclusion 2: y = x-1x + y = 5, y = x-1x + (x-1) = 5zx-1 = 5x = 3, y = x-1y = 2
2X + 5Y = 16 (1) 5x + 2Y = 19 (2) (1) × 5: 10x + 25y = 80 (3) (2) × 2: 10x + 4Y = 38 (4)
(3) (4) get: 21y = 42, y = 2, substitute y = 2 into (1) get: 2x + 5 × 2 = 16, x = 3, so x = 3, y = 2
Formula 1 + formula 2 = 7x + 7Y = 16 + 19 = 35
x+y=35/7=5
Formula 2-1 = 3x-3y = 19-16 = 3
x-y=3/3=1
The sum and difference can be solved
x=（5+1）/2=3
y=5-3=2
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(1) 5 - (2) × 2
25Y-4Y=80=38
21Y=42
Y=21
Substitute (1) to get
2X+105＝16
2X=-89
X=-44.5
Namely:
X=-44.5，Y=21
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Hello, Hanying warm for you
(1) 5 - (2) × 2
25Y-4Y=80=38
21Y=42
Y=21
Substitute (1) to get
2X+105＝16
2X=-89
X=-44.5
Namely:
X=-44.5，Y=21
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Please click the "adopt as satisfied" button in time (or click "satisfied" in the upper right corner of the client)
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Factorization: (1) 2x ^ 2-4x-3 (2) x ^ 2-5x + 5
2x^2-4x-3=0
x=(4±√(-4)^2-4*2*(-3))/4=(2±√10)/2
2x^2-4x-3=2*(x-(2+√10)/2)(x-(2-√10)/2)
We can also get x ^ 2-5x + 5
Take them as the equation of = 0, the solution has root sign, the problem is correct?
2X + 5y-1000 = 13z, 3x + 3Z = 9y, 6x + 8Z + 600 = 5x, how to solve the three element linear equation?
Do you have a look at all the formulas you wrote? The number you solved is very large
2x+5y-1000=13z 1
3x+3z=9y 2
6x+8z+600=5x 3
Solution 2 is x + Z = 3Y, and y = (x + Z) / 3 is carried into Formula 1
We get 11x-34z = 30004
3 times 11 minus 4
We get z = - 4800 / 61, then we get x = 1800 / 61
Y = - 1000 / 61 is obtained from formula 2
2x+5y-1000=13z
3x+3z=9y
6x+8z+600=5x
Solution 2 is x + Z = 3Y, and y = (x + Z) / 3 is carried into Formula 1
We get 11x-34z = 30004
3 times 11 minus 4
We get z = - 4800 / 61, then we get x = 1800 / 61
Y = - 1000 / 61 is obtained from formula 2
The equation - 3T & # 178; - 2T + 4 = 0 is solved by factorization,
We have to use factorization for this problem
3t^2+2t-4=0
t^2+2/3*t-4/3=0
(t+1/3)^2-13/9=0
(T + 1 / 3 + radical 13 / 3) (T + 1 / 3 - radical 13 / 3) = 0
T = - (1 + radical 13) / 3
Or (radical 13-1) / 3
Non factorization
The formula method is simpler
= =
-3t²-2t＋4=-3(t²+2t/3-4/3)=-3[(t+1/3)²-1/9-4/3]=-3(t+1/3)²+13/3=0
So it's not easy to factorize
-3(t+1/3)²+13/3=0
(t+1/3)²=13/9
t+1/3=±√13/3
t=±√13/3-1/3
Factorization: ① 4-4x + X & # 178;; ② X & # 178; + X-6
1.（x-2)（x-2)
2.（x+3)（x-2)
4X + 9y = 97, 5x + 5Y = 65, how to solve the equation
4x+9y=97
5x + 5Y = 65 is reduced to x + y = 13, so y = 13-x. take it into the above equation and get
4x+9(13-x)=97
4x+117-9x=97
117-97=9x-4x
5x=20
X=4
So y = 13-x = 9
4X + 9y = 97, 5 copies
5x + 5Y = 65, after formula 2 * 4
Formula 1 minus formula 2 leads to y = 9 and formula 1 leads to x = 4
4x+9y=97
X=4
Y=9
4*4+9*9=97
5x+5y=65
X=3
y=10
5*3+5*10=65
It's a fight,
9x & # 178; - 16 = 0, find the solution by factorization
9x²﹣16＝0
（3x+4）（3x-4）=0
x1=-4/3 x2=4/3
solution
9x²-16=0
(3x-4)(3x+4)=0
x=4/3
Or x = - 4 / 3
9x²﹣16＝0
(3X）²-4²=0
（3X-4）（3X+4）=0
So 3x-4 = 0 or 3x + 4 = 0
X1=4/3,X2=-4/3
Factorization in the range of real numbers: (1) x & # 178; - 2 (2) 5x & # 178; - 3
(1)x²-2
(2)5x²-3
(1)x²-2
=(x+√2)(x-√2)
(2)5x²-3
=(√5x+√3)(√5x-√3)
Mixed fraction
(1)x²-2
=(x+√2)(x-√2)
(2)5x²-3
=(√5x+√3)(√5x-√3)
Get it, get it
How to do x = 4-5y, 3x-9y = 4 with substitution method
Let's take x = 4-5y into the following equation, which is 3 (4-5y) - 9y = 4, and then solve y