Løsning del 1 utrinn Vår 14

Oppgave 1

a) $831+1196=2027$

b) $987-789=198$

c) $14,2\cdot 3,1=44,02$

d) $1620:120=\frac{1620}{120}=\frac{162}{12}=13,5$

Oppgave 2

a) $3,25\mathrm{h}=3\cdot 60\min +25\min =205\min$

b) $9,3\mathrm{t}=9,3\cdot 1000\mathrm{kg}=9300\mathrm{kg}$

c) $2400{\mathrm{cm}}^3=2400\mathrm{mL}=2,4\mathrm{L}$

d) $36\mathrm{km}/\mathrm{h}=\frac{36}{3,6}\mathrm{m}/\mathrm{s}=10\mathrm{m}/\mathrm{s}$

Oppgave 3

a) $62000=6,2\cdot {10}^4$

b) $((-3{)}^2{)}^2-3^0=9^2-1=81-1=80$

Oppgave 4

a) $\frac{1}{5}+\frac{2}{5}=\frac{1+2}{5}=\frac{3}{5}$

b) $\frac{5}{2}-\frac{2}{3}=\frac{5\cdot 3}{2\cdot 3}-\frac{2\cdot 2}{3\cdot 2}=\frac{15}{6}-\frac{4}{6}=\frac{15-4}{6}=\frac{11}{6}$

c) $\frac{1}{4}\cdot \frac{2}{4}=\frac{1\cdot 2}{4\cdot 4}=\frac{2}{16}=\frac{1}{8}$

d) $4:\frac{2}{3}=4\cdot \frac{3}{2}=\frac{12}{2}=6$

Oppgave 5

a)

$3x=x+8$

$3x-x=x+8-x$

$2x=8$

$x=\frac{8}{2}=4$

b)

$(x+2{)}^2=x^2+6$

$x^2+4x+4=x^2+6$

$4x+4=6$

<math>4x=6-4</math

$x=\frac{2}{4}=\frac{1}{2}$