13.
(x+2)/3=8/15
(x+2)/3=0.53(3 is recurring)
x+2=1.6
x=-0.4
14.
18/x=6
x=3
15.
5/7=10/y+2
5/7=10/14, therefore y+2=14
y=14-2
y=12
16.
Area = 3.6cm x 4.2cm = 15.12cm2
Perimeter = 3.6cmx2 + 4.2cmx2 = 15.6cm
17.
Area = 9mm x 9mm = 81mm2
Perim = 9+9+9+9 = 36cm
18. for the sake of typing, pi=#
Area = #rsquared
= 4x4# square inches
= 16# square inches (totally accurate)
= 50.2 square inches
Circum = #d, d=2xr = 2x4 = 8
=8# square inches (totally accurate)
=15.1 square inches
19.
Area = #rsquared
=81#
=254.5 inches squared
Circum = #d
=18#
=56.5 inches squared
20.
Area = #rsquared
root (36#/#)= radius
root 36 = radius
radius = 6
Circum = #d
=12#
=37.7 cm
21.
4x^5 y^2/2x^2 y = 2x^3 y
22.
(5x^3 y^2)^2 = 25x^6 y^4
23.
(6a^2-7ab-4b^2)-(2a^2-5ab+6b^2) = 4a^2-2ab-10b^2
24.
x^3x^6=x^9
25.
Triangle (right angled, scalene)
26.
Regular Octagon
27.
Parallelogram
28.
Trapezium
29.
Equilateral Triangle
30.
Isosceles Triangle
31.
x^2+3x=0
-b+-rootb^2-4ac all divided by 2a
so, -3+- root(9-0) all over 2
(-3(+-)3)/2 = x
x = 0 or x = -3
32.
x^2-5x-24=0
(x-8)(x+3)=0
x=8 or x=-3
33.
3x^2+x-4=0
(3x+4)(x-1)=0
x=-1.3 (3 is recurring) or x=1
34.
3a + 6a^2
3a(1+2a)
35.
9b^2+12b+4
3b(3b+4)+4
36, 37, 38, you have to do this by yourself, as it is a graph (38 is a horizontal line on -3)
39.
y=4x-3
40.
y=-7/5x+5.8
41.
y=1/6x+3 1/3
42.
y=-4/3 x
43.
(1) s+2t=6
(2) 3s-2t=2
(1)+(2) 4s=8
s=2
subs in (1) 2+2t=6
2t=4
t=2
check in (2)
6-4=2
44.
(1) x-3y=3
(2) 2x+9y=11
(1)x3 3x-9y=9
(2) 2x+9y=11
(1)+(2) 5x=20
x=4
subs x=4 in (1)
4-3y=3
3y=1
y=1/3
check in (2)
8+3=11
45.
SDP = 15x15 = 225 square inches
RP = 64# = 201.1 square inches
SDP's pizza is bigger.
SDP = $9/225 square inches = $0.04 per square inch
RP = $8.75/201 square inches = $0.044 per square inch
SDP's pizza is the better buy
46.
1 gallon = 128 ounces
therefore, 1 gallon = 128/8, eight oz glasses
you can get 16 eight ounce glasses from 1 gallon, but there are 1.5 gallons, so you can get 1.5x16 glasses from the pitcher. 1.5x16 = 24 glasses.
I deserve a merit (these stupid things given out at our school by teachers when you do something good)