Question

1. Desfaceti parantezele şi reduceţi termenii asemenea:
a) 3(6-5x)+17x-10;
b) 8(3y + 4)-29y+14;
c) 2(4+a) -8;
d) 3(3-X)-6;
e) -3(2 - x - y) + x - 3y;
1) 7(2x-3)+ 6x-12;
g) 2-(7,3-1,6a) +3,2a -9,6;
h) -5-(0,3x +1,7)+12,5-8,5x;
i) -4.(3,3--8a)+4,8a +5,2;
j)-(-x²-x³)+2(x²+x³)-3x³:
k) -a-(3-5)+2ab;
l) 2a(1-a)+a²-2a​

Answer 1

Răspuns:

a) 3(6-5x)+17x-10=0 <=> 18-15x+17x-10=0 <=> 2x+8=0 <=> 2x= -8 <=> x= -4

b) 8(3y + 4)-29y+14=0 <=> 24y+32-29y+14=0 <=> -5y+46=0 <=> -5y= -46 <=> 5y=46 <=> y=46/5 <=> y=9,2

c) 2(4+a) -8=0 <=> 8+2a-8=0 <=> 2a=0 <=> a=0

d) 3(3-x)-6=0 <=> 9-3x-6=0 <=> -3x+3=0 <=> -3x= -3 <=> 3x=3 <=> x=1

e) -3(2-x-y)+x-3y=0 <=> -6+3x+3y+x-3y=0 <=> 4x-6=0 <=> 4x=6 <=> x=6/4 <=> x=3/2

f) 7(2x-3)+ 6x-12=0 <=> 14x-21+6x-12=0 <=> 20x-33=0 <=> 20x=33 <=> x=33/20

g) 2(7,3-1,6a)+3,2a-9,6=0 <=> 14,6-3,2a+3,2a-9,6=0 <=> 14,6-9,6=0 <=> 5=0

h) -5(0,3x+1,7)+12,5-8,5x=0 <=> -1,5x-8,5+12,5-8,5x=0 <=> -10x+4=0 <=> -10x= -4 <=> 10x=4 <=> x=4/10 <=> x=2/5 <=> x≈0,4

i) -4(3,3-8a)+4,8a+5,2=0 <=> -13,2+32a+4,8a+5,2=0 <=> 36,8a-8=0 <=> 36,8a=8 <=> a=8/36,8 <=> a=5/23

j)-(-x²-x³)+2(x²+x³)-3x³=0 <=> x²+x³+2x²+2x³-3x³=0 <=> 3x²+0=0 <=> 3x²=0 <=> x²=0 <=> x=0

k) -a-(3-5)+2ab=0 ăsta sigur este bine scris?

l) 2a(1-a)+a²-2a=0 <=> 2a-2a²+a²-2a=0 <=> -a²=0 <=> a=0