Matlab, how to draw two curves in a coordinate system, plot (x1, X2, Y1, Y2) or how

Plot has the following usage:
plot(Y)
plot(X1,Y1,...,Xn,Yn)
plot(X1,Y1,LineSpec,...,Xn,Yn,LineSpec)
plot(X1,Y1,LineSpec,'PropertyName',PropertyValue)
plot(axes_ handle,X1,Y1,LineSpec,'PropertyName',PropertyValue)
h = plot(X1,Y1,LineSpec,'PropertyName',PropertyValue)
Examples are as follows:
x1 = -pi:.1:pi;
y1 = sin(x1);
x2=0:0.1:2*pi;
y2=cos(x2);
Plot (x1, Y1, X2, Y2);% draw all at once
In addition, if you want to draw only one curve at a time, you can:
x1 = -pi:.1:pi;
y1 = sin(x1);
Plot (x1, Y1);% plot 1
Hold;% hold image
x2=0:0.1:2*pi;
y2=cos(x2);
plot(x2,y2);

It is known that the function f (x) whose domain is r satisfies f (- x) = - f (x + 4). When x > 2, f (x) increases monotonically

Suppose X1 > 2, then (x1-2) (x2-2)

If x ^ 2-4x-1 = 0, then the value of 3x ^ 2 + 12x-5
It has been corrected: if x ^ 2 + 4x-1 = 0, then the value of 3x ^ 2 + 12x-5

Because x ^ 2 + 4x-1 = 0
Then x ^ 2 + 4x = 1
that
3x^2+12x-5 = 3(x^2+4x) -15 = 3*1-15 = -12

What's 2 out of 9 times 5 by 27 out of 28? What's 9 out of 4 times 12 plus 5 out of 3 times 12
I want the formula

2/9*5*27/28=2*5*27/(9*28)=15/14
9/4*12+5/3*12=12*(9/4+5/3)=12*(27+20)/12=47

The equation 3: 8 = 24: x36x = 543x + 38x = 1214x-3 × 9 = 29

（1）3：8=24：x 3x=8×24 3x÷3=192÷3 x=64；...

How to calculate (5 / 6 + 4 / 9-2 / 3) * 18?

(5/6+4/9-2/3)*18
=5/6X18+4/9X18-2/3X18
=15+8-12
=11

ABC in quadratic function
Y = ax square + BX + C
What do a, B, C in represent respectively? What is the meaning in the image?

a> 0, parabolic opening upward; a

8+88+888+8888+88888+888888+8888888

=8×（1+11+111+1111+11111+111111+1111111）
=8×1234567
=9876536

The known set a = {x | x

CRB = (- ∞, 1] u [3, + ∞) because a ∪ CRB) = R, a must contain: (1,3) so a must be greater than or equal to 3, that is, the value range of real number a is [3, + ∞)

Matlab, how to draw two curves in a coordinate system, plot (x1, X2, Y1, Y2) or how