Question

aceste 2 ex. ,...... .....

Answer 1

31.
a.
x+y+z+24=48
x+y+z=48-24
x+y+z=24
15+2z+2y+2x=15+2(x+y+z)=15+2$*$24=15+48=63
b.
3x+3y+23=65
3(x+y)=65-23
3(x+y)=42
x+y=42 : 3 =14
2x+2y+27=2(x+y)+27=2$*$14+27=28+27=55
c.
x+3y+2z+16=50
x+3y+2z=50-16
2+3y+2z=34    /$*2$
2x+6y+4z=68
2x+6y+4z+12=68+12=80
32.
a.
 1   +2   +3.................+29
29+28 +27+................+1
30+30+30...................+30
30$*$29$:$2=870$:$2$=$435
b.
5+10+15+20+.......................+125
5(1+2+3+4+..........................+25)
5(26$*$25$:$2)
5(650 : 2)=5$*$325$=$1625
c.
10+20+30+...........................+200
10(1+2+3+..............................+20)
10(20$*$21$:$2)=10(420$:$2)=10$*$210=2100
d.
19+20+21+22+......................+39
39$*$40[tex]: [/tex]2$-$18$*$19$:$2
780$-$171$=$609