Question

Daca x = 5 si a + b = 13, calculati:

a) 3 • x + 7 • a + 7 • b;
b) x • a + x • b - 50;
c) 10 • x + (4 • a + 4 • b);
d) (4 • a + 4 • b - 2 • x) • (2 • a + 2 • b + x).

Answer 1

Răspuns:

Explicație pas cu pas:

Daca x = 5 si a + b = 13, calculati:

a) 3 • x + 7 • a + 7 • b = 3*5 + 7(a+b) = 15 + 7*13 = 15 + 91 = 106;

b) x • a + x • b - 50 = x(a+b) - 50 = 5*13 - 50 = 65 - 50 = 15;

c) 10 • x + (4 • a + 4 • b) = 10*5 + 4(a+b) = 50 + 4*13 = 50+52 = 102;

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

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

(4*13 - 2*5)(2*13 + 5) =

(52 - 10)(26 + 5) =

42*31 =

1302.