Question

Este metoda factorului comun, va roog, dau coroana și 100 de puncte​

Answer 1

a)

ab+ac+ad=80

b+c+d=40

a(b+c+d)=80

a ori 40=80

a=80/40

a=2

b)

ab^2+ac^2=100

a=5

a(b^2+c^2)=100

5(b^2+c^2)=100

b^2+c^2=100/5

b^2+c^2=20

c)

ab+ac+db+dc=150

a+d=25

(a+d)(b+c)=150

25(b+c)=150

b+c=150/25

b+c=6

d)

i)

1997 ori 1998 - 1997 ori 1999 + 1997 =

1997(1998-1999+1)=

1997(-1+1)=

1997 ori 0 = 0

ii)

2345 ori 88 + 920 ori 2345 - 8 ori 2345 =

2345(88+920-8) =

2345 ori 1000 = 2345000

Answer 2

$ab + ad + ac = 80 \\ b + c + d = 40 \\ a(b + d + c) = 80 \\ a \times 40 = 80 \\ a = \frac{80}{40} \\ a = 2 \\ b) {ab}^{2} + {ac}^{2} = 100 \\ a = 5 \\ {b}^{2} + {c}^{2} = \\ a( {b}^{2} + {c}^{2} ) = 100 \\ 5( {b}^{2} + {c}^{2} ) = 100 \\ {b}^{2} + {c}^{2} = \frac{100}{5} \\ {b}^{2} + {c}^{2} = 20 \\ c) ab + ac + db + dc = 150 \\ a + d = 25 \\ a(b + c) + d(b + c) = 150 \\ (a + d) +( b + c) = 150 \\ 25 + (b + c) = 150 \\( b + c) = \frac{150}{25} \\ b + c = 6$