Using the matrix method, the equations are: 2x1-3x2 + x3-x4 = 33x1 + x2 + X3 + X4 = 0 4x1 - X2 - x3-x4 = 7 - 2x1-x3 + X3 + X4 = - 5

Using the matrix method, the equations are: 2x1-3x2 + x3-x4 = 33x1 + x2 + X3 + X4 = 0 4x1 - X2 - x3-x4 = 7 - 2x1-x3 + X3 + X4 = - 5

Coefficient matrix=
2 -3 1 -1 3
3 1 1 1 0
4 -1 -1 -1 7
-2 -1 1 1 -5
r4+r3,r3*(1/7)
2 -3 1 -1 3
3 1 1 1 0
1 0 0 0 1
-2 -1 1 1 -5
r1-2r3,r2-3r3,r4+2r3
0 -3 1 -1 1
0 1 1 1 -3
1 0 0 0 1
0 -1 1 1 -3
r1-3r2,r4+r2
0 0 4 2 -8
0 1 1 1 -3
1 0 0 0 1
0 0 2 2 -6
r4*(1/2),r1-4r4,r2-r4,
0 0 0 -2 4
0 1 0 0 0
1 0 0 0 1
0 0 1 1 -3
r1*(-1/2),
0 0 0 1 -2
0 1 0 0 0
1 0 0 0 1
0 0 1 0 -1
Exchange bank
1 0 0 0 1
0 1 0 0 0
0 0 1 0 -1
0 0 0 1 -2
The solutions of the equations are: X1 = 1, X2 = 0, X3 = - 1, X4 = - 2

Given that x1, X2, X3 and X4 are in equal proportion sequence, and X1 and X4 are two of the equations 2x & # 178; + 3x-1 = 0, then x2 + X3=

x1+x4=2x1+3d
x2+x3=2x1+3d
x2+x3=x1+x4
X1, X4 are two of the equations 2x & # 178; + 3x-1 = 0, which are derived from the Widal theorem
x1+x4=-3/2
x2+x3=-3/2

If in the product of (x2 + ax-b) (2x2-3x + 1), the coefficient of X3 is 5 and the coefficient of X2 is - 6, find a and B

The original formula = 2x4-3x3 + x2 + 2ax3-3ax2 + ax-2bx2 + 3bx-b = 2x4 + (2a-3) X3 + (1-3a-2b) x2 + (a + 3b) X-B ∵ the coefficient of X3 is 5, the coefficient of X2 is - 6, ∵ 2a-3 = 5, 1-3a-2b = - 6, the solution is a = 4, B = - 52

In the product of (x2 + ax + b) (2x2-3x-1), if the coefficient of X3 is - 5 and the coefficient of X2 is - 6, then a=______ ，b=______ ．

(x2 + ax + b) (2x2-3x-1) = 2x4-3x3-x2 + 2ax3-3ax2-ax + 2bx2-3bx-b = 2x4 + (2a-3) X3 + (2b-3a-1) X2 - (a + 3b) X-B, according to the meaning of the question: 2a-3 = - 5, 2b-3a-1 = - 6, the solution is: a = - 1, B = - 4