Matematyka z kluczem 8. Zeszyt ćwiczeń | Strona 32 | Zadanie 1
Oblicz wartość wyrażenia dla podanych wartości x i y.
a)
2 (x + y) – xy = 2 ∙ (2 + 5) – 2 ∙ 5 = 2 ∙ 7 – 10 = 14 – 10 = 4
b)
6x + 5y – xy = 6 ∙ 2 + 5 ∙ 3 – 2 ∙ 3 = 12 + 15 = 6 = 21
c)
3 – 2(x- y) + 7 = 3 – 2 ∙ ( 3 – 2) + 7 = 3 – 2 ∙ 1 + 7 = 3 – 2 + 7 = 8
d)
8 – 5 (2x + y) + 6 = 8 – 5 ∙ ( 2 ∙ (-1) + 4) + 6 = 8 – 5 ∙ (-2 + 4) + 6 = 8 – 5 ∙ 2 + 6 = 8 – 10 + 6 = 4
e)
x2 + 2xy + 5y = (-3)2 + 2 ∙ (-3) ∙ (-1) + 5 ∙ (-1) = 9 + 2 ∙ 3 + (-5) = 9 + 6 – 5 = 10