Х*у = 3/5*(-15) = - 9.
Тогда 4 - 1/3*(-9) = 4 + 3 = 7.
Ответ: 7.
а) 2х*(с-3) - у*(с-3) = (2х-у)*(с-3)
б) 5х*(3а+2b) - 7y*(2b+3a) = (3a+2b)*(5x-7y)
в) 8p*(7q+1)-1*(1+7q) = (1+7q)*(8p-1)
B1 = 4
b3 - b5 = 32/81
b1·q² - b1·q^4 = 32/81
4q² - 4q^4 -32/81 = 0 |: 4
q² - q^4 -8/81 = 0
81q² - 81q^4 -8 = 0
81q^4 - 81q² +8 = 0
<em>q²= t</em>
81t² -81t +8 = 0
D = b² - 4ac = 6561 - 4·81·8 =81(81 -32) = 81·49
t1 = (81 +63)/162 = 144/162
t2 = (81 - 63)/162 = 18/162=1/9
а) q² = 144/162
q = 12√2/18
S = b1/(1-q)
S = 4/(1 - 12√2/18)
б) q² = 1/9
q = 1/3
S = b1/(1 - q)
S= 4/(1 - 1/3) = 4 : 2/3 = 6
1)16а^6=(4a^3)^2
2)100m^8n^4=(10m^4n^2)^2
3)25/81x^6y^12=(5/9 x^3y^6)^2
4)169/225a10b2=(13/15a^5b)^2
5)3,24m^4p^14=(1,8m^2p^7)^2