1.persamaan garis melalui titik P(1, 2) dan

1.) 3x+y=8
y=-3x+8

m1=m2=-3
(1,2)
y-b=m(x-a)
y-2=-3(x-1)
y-2=-3x+3
y=-3x+5

2.) (1,4) dan (-2,-5)
y-y1/y2-y1=x-x1/x2-x1
y-4/-5-4=x-1/-2-1
y-4/-9=x-1/-3
-3(y-4)=-9(x-1)
-3y+12=-9x+9
-3y=-9x+9-12
-3y=-9x-3
_______÷-3
y=3x+1

*tipot sb y,x=0
y=3x+1
y=3(0)+1
y=1
(0,1)

3.) 2x+5y=-3 (x 3)
3x-2y=5 (x 2)

6x+15y=-9
6x-4y=10
________-
19y=-19
y=-19/19
y=-1

2x+5y=-3
2x+5(-1)=-3
2x-5=-3
2x=-3+5
2x=2
x=2/2
x=1

4.) x/2+y/4=7/4
______________x 4
2x+y=7

x/4-y/3=9/4
_________x 12
3x-4y=27

2x+y=7(x 4)
3x-4y=27(x 1)

8x+4y=28
3x-4y=27
________+
11x=55
x=55/11
x=5

2x+y=7
2(5)+y=7
10+ y=7
y=7-10
y=-3
Penyelesaiannya (5,-3)

5.) Misal
Lebar=x
Panjang=x+4

Kell=2(p+l)
36=2(x+4+x)
36=2(2x+4)
36=4x+8
-4x=8-36
-4x=-28
x=-28/-4
x=7

panjang=x+4
=7+4
=11
lebar=x=7

L=p x l
=11 x 7
=77 cm²