3 simple math problems to solve, 3 simple math questions.

The first question is incorrect.

Question 2 a = 14

5x+y=3（1）

x-2y=5（2）

From (2) x=5+2y(3) to (1) 5(5+2y)+y=3 11y=-22 y=-2 to bring in (3)x=1

Bring x=1 y=-2 into ax+5y=4 a*1+5*(-2)=4 a-10=4 a=14

Question 3 Xiaoqiang is 16 years old and his uncle is 28 years old.

The ages of Xiaoqiang and Uncle are x and y respectively. Rule.

x-(y-x)=4

x+(40-y)=y

x=16,y=28

Xiaoqiang is 16 years old and his uncle is 28 years old.

1. (There is a problem with the question).

2. The system of equations about x and y 5x+y=3 has the same solution as x-2y=5, ax+5y=4

Simultaneous equations 5x+y=3

x-2y=5 ②

2, get 10x+2y=6

Get 11x=11

x=1 brings x=1 into to get 5*1+y=3

y=-3 gives x=1

y=-3 brings x=1 into ax+5y=4, and we get.

y=-3a+5*(-3)=4

a-15=4

a=193, solution: Set Xiaoqiang is x years old this year, and his uncle is y years old this year.

Let Xiaoqiang's age be A, and his uncle's age be B

x-(y-x)=4

x+(40-y)=y

Organize the system of equations, get.

2x-y=4①

x-2y=-40②

2 gets 2x-4y=-80

3y=84

y=28 substitute y=28 into it.

x=16A: Xiaoqiang is 16 years old and his uncle is 28 years old.

The first question, there is a problem with the question, condition 2 and condition 3 are added, and the equation is 0, how can it be -6

In the second problem, there is the same solution, which means that the x of the two formulas is equal, and the y-generation x5x+y=3 is replaced by x=(3-y) 5 and the other formula is transformed into x=5+2y, and the simultaneous equation y-3 5=5+2y solves y=-2

Substituting the original system of equations to solve x x = 1

Finally, we find a=14

The third question is to set the uncle to be X years older than Xiaoqiang, Xiaoqiang's age is used in generation A, and the uncle is in generation B.

When I was your age, you were only four years old, which means a-x=4(1) b-x=a, and when you were my age, a+ x =b(2) I would be forty b+x=40(3).

According to the equation listed.

2), (3) a+x+x=40

According to (1) a=4+x

Then, according to the two formulas just obtained, x=12, a=16, and b=28 are solved

a=14 Let Xiaoqiang's age be a and his uncle's age be b

a-(b-a)=4

a+(40-b)=b

a=16,b=28

Xiaoqiang is 16 years old and his uncle is 28 years old.

I don't know anything = = thus. Anonymity.

The first question is wrong.

10*x-2y=6

10x-2y+（x-2y）=6+5

x=1y=-2

a=143.Xiaoqiang is 16 years old and his uncle is 28 years old.

The first question should have been written incorrectly. There is no solution.

Question 2 a = 14

Question 3 Xiaoqiang is 16 years old and his uncle is 28 years old.

1. I can't do it, 2 and 3 can't be established at the same time, are you sure you didn't copy the question wrong?

2. The two equations are solved separately to obtain y=-2 and x=1, then a*1+5*(-2)=4, and a=4+10=14

3. Set Xiaoqiang is x years old this year, and his uncle is y years old this year, because the age gap between the two remains the same, so x-4=y-x=40-y, and the age of the two this year is x+y=44, and the age difference is y-x=12, so x=16, y=28

Add the two formulas and see what happens. So this question is wrong.

2.The two forms are combined, and the common point of the two straight lines is substituted for a:a=14

3.Let Xiaoqiang, uncle x, and y years old respectively, and the equation can be x-(y-x)=4 y+(y-x)=40

I don't understand why you posted this, and you can see it at a glance, give me the score, don't play tricks.

The first question is wrong.

x=1 y=-2, so a=14

Set strong x years old, uncle y years old 2y-x=40 2x-y=4 get x=16 y=28

1: Give 1 2 to the two respectively, and then become a trigonometric function, cos30sinx+sin30cosx=sin(30+x).

2: As in the first question, multiply 1 2 by 2, i.e. 2*( 2 2sinx- 2 2cosx) = 2sin(45-x).

3：2√2(1/2cosx-√3/2sinx)=2√2cos(60+x)

1, it is known that the terminal edge of the foot passes through the annihilation attack of Changdian's Pao P (then a>0 sin =4 5 cos =3 5 a, "Zen Pei 0sin =-4 5 cos =-3 5

2. Compare the size of sin(-23-5)cos23>cos45

3, tan +1 = 0, the solution set is k +3 4, known cos = 1 5 and tan <0 then sin = -2 root number 6 54, f(x) = 5x+1 then f(x+1) = 5x+6