Two very simple equation problems!! Ask for advice!

**The above is the solution, there are infinite groups of solutions for these two systems of equations, the s in the first solution and the a in the second solution are parameters, and their range is the whole real number.

Four unknowns, three equations, there must be an infinite number of solutions.

1.a=6s substitution

6s-4=10s-20d

4s=20d-4

s=5d-1

a=30d-6

Substituting 30d-6+12=3y+18d

y=4d+2

If you have studied linear algebra, the solution of the equation is (a,s,d,y) = (-6,-1,0,2) + k(30,5,1,4) k is any real number.

a=d+4d-2y=-1 --d=2y-1, a=2y+3a+s-d=-1 --2y+3+s-2y+1=-1 --s=-5, so (a,s,d,y)=(3,-5,-1,0)+k(2,0,2,1) k is any real number.

If you haven't studied linear algebra, the easiest way to express this answer is:

1. a=30d-6

s=5d-1

y=4d+2

2. a=2y+3

s=-5d=2y-1

Substituting a=6s into a-4=10s-20d is obtained.

6s-4=10s-20d, simplified to d=

Substituting a=6s into a+12=3y+18d obtains.

6s+12=3y+18d, substitute d=get.

6s+12=3y+, launched.

Replace this equation s,y with x,y to make it easier for the landlord to understand.

Then, the landlord draws this straight line on the coordinate axis, and the points on the straight line are all solutions.

The second one is the same approach. Let's try it for myself

First turn him into a 3-element system of equations, then turn it into a 2-element system of equations, and then solve him.

The equation should be wrong. 5x=2y+4=2y+3, there is no solution... That is, the Zen hall has no solution.

The second argument is x=32 25, y=-29 25

x+7y=m+1 lead hopper.

2x-y=4 ②

x+y=2 ③

De: then which 3x=6

x=2 substitute x=2 to get: y=0

Substituting x=2 y=0 into Huai staring mill obtains: 2=m+1m=1, then 2m+1=3

Are you in your first year of junior high school? Me too.

What do the braces mean? You just don't fight.

Solution: Multiply 6 on both sides of the first equation.

3x-9+2y-4=18

Multiply 6 on both sides of the second equation to get you.

2x-6+3y-6=12

Namely. 3x+2y=31

2x+3y=24 （2）

1) x2-(2) x3.

5y=-10

y=2 substituting y=2 into (1) gives x=9

The solution of the system of equations is x=9, y=2, thank you!

Solution: Replace x=2y+4 3

Substituting y=3x-4 3 obtains: reed coarseness.

y=3(2y+4/3)-4/3

y=6y+4-4/3

5y=4-4/3

y=-8 residue 15

Substitute y=-8 15 into x=2y+4 3.

x=2×-8/3+4/3

x=4/15

2) Formula substitution into (1), type Qin x=2(3x-4 3)+4 3=6x-4 3,5x=4 3,x=4 15

y=3x-4 3=4 Fiber mill 5-4 Rent destruction bucket 3=-8 15