| 1A | 1. A=lw A=29.5X21 A=619.5cm² |
2. A=½bh A=½x15x8.5 A=63.75cm² |
3. A=(a+b)h÷2 A=(9+4)x4÷2 A=26cm² |
4. A=pr² A=3.14x1.5² A=7.065cm² |
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WHY ALGEBRA? ANSWERS
| 1A | 1. A=lw A=29.5X21 A=619.5cm² |
2. A=½bh A=½x15x8.5 A=63.75cm² |
3. A=(a+b)h÷2 A=(9+4)x4÷2 A=26cm² |
4. A=pr² A=3.14x1.5² A=7.065cm² |
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| 3A | 1. 113.10cm² | 2. 254.47cm² | 3. 15393.80cm² |
| 3B | 1. 14.14cm² | 2. 38.48cm² | 3. 104.72cm² |
| 3C | 1. A=LW+lw A=(10x6)+(12x4) A=60+48 A=108cm² |
2. A=LW+lw A=(20x8)+(12x2) A=160+24 A=184cm² |
3. A=LW+lw A=(6x5)+(7x17) A=30+119 A=149cm² |
| 4A | 1. A=12 | 4. D=21 | 7.L=25 | 10. P=16 | 13. s=144 | 16. V=2 | 19. y=3 |
| 2. b=1 | 5. e=-3 | 8. m=6 | 11. Q=36 | 14. t=23 | 17. W=1 | 20. z=10 | |
| 3. c=11 | 6. k=15 | 9. n=20 | 12. R=36 | 15. u=59 | 18. x=2 |
| 4B | 1. A=(a+b)h÷2 A=(7+9)5÷2 A=40 |
3. V=pr²h÷3 V=px5²x13÷3 V=340.3cm³ |
5.
T=g-(a÷500) T=21-(32000÷500) T=-43°C |
| 2. s=d÷t s=150÷2 s=75 |
4. S=2pr(r+h) S=2xpx3(3+12) S=282.7cm² |
| 5A | 1. A=lw 20=5w 4=w |
2. A=lw 50=12w 4.17=w |
3. A=lw 24.5=7w 3.5=w |
| 5B | 1. l=6.25 | 3. h=8 | 5. d=39.79 | 7. a=24 | 9. m=9.8 |
| 2. a=7.5 | 4. s=4.29 | 6. l=7.5 | 8. g=5.92 | 10. r=17 |
| 5C | 1.d=st d=60x4 d=240 miles |
2. d=st 130=sx3 43.3 mph = s |
3. d=st 220=45t 4.89 hrs = t |
5D | 1. 12 N 2. 2.33 N/m² 3. 1.42 m² |
| 5E | 1. P=2l+2w 20=2l+(2x4) 20=2l+8 12=2l 6=l |
2. P=2l+2w 28=2l+(2x3) 28=2l+6 22=2l 11=l |
3. P=2l+2w 50=2l+(2x12) 50=2l+24 26=2l 13=l |
4. P=2l+2w 30=2l+(2x4.5) 30=2l+9 21=2l 11.5=l |
5. P=2l+2w 47=2l+(2x8.4) 47=2l+16.8 30.2=2l 15.1=l |
| 5F | 1. x=1, y=2 | 2. x=3, y=4 | 3. x=1.5,
y=3.5 |
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| 4. x=1, y=2 | 5. x=4, y=5 | 6. x=2.5 y=2.25 |
| 6A | 1. a=180-(95+48) a=37° |
2. b=180-(25+77) b=78° |
3. c=180-(36+70) c=74° |
| 6B | 1. 2x+110=180 2x=70 x=35° |
2. 2x+24=180 2x=156 x=78° |
3. x+(2x64)=180 x=180-128 x=52° |
| 6C | 1. h²=a²+b² h²=7²+4² h²=65 h= 8.062 |
2.h²=a²+b² 10²=5²+b² 100=25+b² 75=b² 8.66=b |
3. h²=a²+b² 11²=a²+7² 121=a²+49 72=a² 8.485=a |
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| 7A | 1. 5p=30 p=30÷5 p=6 |
5. f-8=16 f=16+8 f=24 |
9. 5n+7=45 5n=45-7 5n=38 n=38÷5 n=7.6 |
13. 6s-17=3 6s=20 s=3.33 |
| 2. 8v=36 v=36÷8 v=4.5 |
6. g-15=12 g=12+15 g=27 |
10. 7p+14=30 7p=30-14 7p=16 p=16÷7 p=2.286 |
14. 8t-12=25 8t=37 t=4.625 |
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| 3. d+7=16 d=16-7 d=9 |
7. h÷5=7 h=7x5 h=35 |
11. 9q+21=102 9q=102-21 9q=81 q=81÷9 q=9 |
15. 12u-9=30 12u=39 u=3.25 |
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| 4. e+11=26 e=26-11 e=15 |
8. k÷8=6 k=6x8 k=48 |
12. 4r-16=12 4r=12+16 4r=28 r=28÷4 r=7 |
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| 7B | 1. a+9=12-a 2a+9=12 2a=3 a=1.5 |
3. 4c+7=2c+15 2c+7=15 2c=8 c=4 |
5. 7x-8=5x+3 2x-8=3 2x=11 x=5.5 |
7. 8x-4=5x+1 3x-4=1 3x=5 x=1.4 |
| 2. b-6=2-b 2b-6=2 2b=8 b=4 |
4. 3d-5=d+11 2d-5=11 2d=16 d=8 |
6. 9y+5=3y+35 6y+5=35 6y=30 y=5 |
8. 3y+9=5y-8 9=2y-8 17=2y 8.5=y |
| 8A | 1. C=pd 90 = pd 90÷p = d 28.6cm =d |
3. A = ½bh 70 = ½x20h 70 = 10h 70÷10 = h 7metres = h |
5. s=d÷t s= 160 ÷2 s= 80 mph |
7. P = 2(l+w) 22 = 2(7+w) 11 = 7+w 4 m = w |
| 2. A=l² 40 = l² Ö40=l 6.3cm = l |
4. V = lwh 240 = 15x8h 240 = 120h 2cm = h |
6. A = pr² 314 = pr² 314÷p = r² 100 = r² 10=r |
8. F = ma 150 = 20a 7.5 m/s² = a |
| 8B | 1.W=hr W=38x10 W=£380 |
2. W=hr 100=hxr 100÷7=h 14.3hrs=h |
3. C=lwp C=5x4x11 C=£220 |
C=Ap 110=15p 110÷15=p £6.67 per m² =p |
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