Prosze o zrobienie, daje max punktów startowych (nowy)   Oczywiście chce obliczenia  

Zad.1 x+y =20 x-y = 10 -------- 2x = 30  /:2 x = 15 15+y = 20 y = 20-55   y =5 x=15 Od. C   Zad.2 Dane  jabłka :  x gruszki  : y x+y = 6 x = 0,5 y Odp D   Zad.3 Ewelina ma czekolad : x Maciek ma : x+ 2   x+ x+2 =10 2x = 10-2 2x = 8  /:2 x = 4  czekoady Ewy Maciek = x+2 = 4+ 2 = 6 Odp. B (6,4)   Zad.4 x+y+4 = 0 3x +4y+6 = 0   x+y = - 4    /* (-4) 3x +4y = -6   -4x -4y = 16 3x +4y = -6 -------------- -x = 10  / *(-1) x= - 10 -10 +y+ 4 = 0 y = 6 x = -10 Odp. C   Zad. 5 Króliki : x Gęsi  :  y   Głowy: x+y = 13 x = 13-y nogi 4x +2y = 42 Odp. B   Zad. 6 Banany :  x Winogron :  y 3x + 5y = 26 4x +7y = 36   3x = 26-5y 4x +7y = 36   x = (26-5y)/3 4*[ (26-5y)/3] +7y = 36   /*3   x = (26-5y)/3 4(26-5y) +21y = 108   x = (26-5y)/3 104 -20y +21y = 108   x = (26-5y)/3 y = 108-104   y = 4 x = (26-5*4)/3   y = 4 x= 6/3   y=4zł x=2 zł Odp. A. 4 zł , 2 zł   Zad.7 (x+y)/4 + 1 = x/2 + (13-y)/4    /*4 2(x-1) + 9 = 2 (y+1)-5   x+y + 4 = 2x +13 –y 2x – 2 + 9 = 2y + 2 -5   x+y -2x +y = 13 -4 2x -2y = 2-5-9+2   -x + 2y = 9 2x-2y = -10 --------------- x = -1 1 +2y = 9 2y = 9-1 2y =8  /:2 y  =  4 X = -1 Odp. A jedno para liczb (-1 ,4)   Zad. 8 Wiek córki  : x Wiek matki : y x+y=46 x-10 = 2y    x +y = 46      /*2 x-2y = 10    2x + 2y = 92 x-2y = 10 --------------- 3x = 102   /:3 x = 34 wiek matki 34 +y = 46 Y = 46 – 34 = 12 wiek córki  za 6 lat matka  : 34+6= 40  lat 46-34=12 Córka   12+6= 18    lat Odp. B .  18 lat  i 40 lat   Zad.9 1% = 1/100   0,75x – 66i2/3% y = 1 33 i1/3 % x+ 1/4 y = 7   3/4x – 200/3 * 1/100 y = 1 100/3 * 1/100x + 1/4y = 7   3/4x – 2/3y = 1       /*12 1/3x + 1/4y = 7      /*12   9x -8y =12 4x + 3y =84   9x = (12+8y)  /:9 4x+3y = 84   x = (12+8y)/9 4[ (12+8y)/9] +3y = 84    /*9   x = (12+8y)/9 4(12+8y) + 27y = 756   x = (12+8y)/9 48 +32y +27y = 756   x = (12+8y)/9 59y = 756 -48   x = (12+8y)/9 59y = 708    /:59   x = (12+8y)/9 y = 12   x= (12+8*12)/9 y=12   x = 108/9 y = 12   x=12 y=12 Odp. D (12,12)   Zad. 10 a/b = 2/5 a-7/2b = 3/20   5a = 2b 20(a-7)= 6b   a = 2b/5 20a – 140 = 6b   a = 2b/5 20 *2b/5  -140 = 6b   a = 2b/5 8b -6b = 140   a = 2b/5 2b = 140  /:2   b = 70 a = 2*70/5   b = 70 a = 28   a+b = 28 + 70 = 98   Odp. C  98