Question

3 Dacă x = 5 şi a+b=13, calculați:​

Answer 1

Răspuns:

a) 3 x 5 + 7 x a + 7 x b =

15+7a+7b=

15+7(a+b)=

15+7x13=

15+91=106

b) 5 x a + 5 x b - 50=

5a+5b-50=

5(a+b)-50=

5 x 13 - 50= 65-50= 15

c) 10 x 5 + (4 x a + 4 x b) =

50+4a+4b=

50+4(a+b)=

50+4x13=

50+52=102

d) (4 x a + 4 x b - 2 x 5) x (2 x a + 2 x b + 5)=

(4a+4b-10) x (2a+2b+5)=

4(a+b)-10x2(a+b)+5=

(4x13)-10x(2x13)+5=

(52-10)x(26+5)=

42x31=1302