### The Maxima on-line user's manual

Algebra Calculator

#### Backsubst

-- Option variable: backsubst Default value: `true`

When `backsubst` is `false`, prevents back substitution in `linsolve` after the equations have been triangularized. This may be helpful in very big problems where back substitution would cause the generation of extremely large expressions.

```          (%i1) eq1 : x + y + z = 6\$
(%i2) eq2 : x - y + z = 2\$
(%i3) eq3 : x + y - z = 0\$
(%i4) backsubst : false\$
(%i5) linsolve ([eq1, eq2, eq3], [x,y,z]);
(%o5)             [x = z - y, y = 2, z = 3]
(%i6) backsubst : true\$
(%i7) linsolve ([eq1, eq2, eq3], [x,y,z]);
(%o7)               [x = 1, y = 2, z = 3]```

```(%o1)                                true
(%i2) ```

### Related Examples

##### backsubst-eliminate-false-linsolve_params-linsolvewarn-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: I0=I+EI+EIS;

Calculate

##### backsubst-linsolve-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: k1*E*S-k11*ES-kc...

Calculate

##### backsubst-linsolve_params-linsolvewarn-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: I0=I+EI+EIS;

Calculate

##### backsubst-linsolve

eq_x: px + lambda * u...

eq_y: py + lambda * u...

eq_z: pz + lambda * u...

Calculate

##### backsubst

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: k1*E*S-k11*ES-kc...

Calculate

##### backsubst-linsolve_params-linsolvewarn-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: I0=I+EI+EIS;

Calculate

##### backsubst-linsolve_params-linsolvewarn-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: I0=I+EI+EIS;

Calculate

##### backsubst-linsolve

eq_x: px + lambda * u...

eq_y: py + lambda * u...

eq_z: pz + lambda * u...

Calculate

##### backsubst-linsolve_params-linsolvewarn-true

eq1: v=kcat*ES+k2*EIS;

eq2: E0=E+ES+EI+EIS;

eq3: k1*E*S-k11*ES-kc...

Calculate

##### backsubst-debugmode-globalsolve-integrate-linsolve_params-linsolvewarn-true

/*Biegelinie für Träg...

globalsolve : true;

debugmode: true;

Calculate