Ответ:
Графики ==================================
Объяснение:
1)
х+3у=13
х=3-0,5у
3-0,5у+3у=13
х=3-0,5у
2,5у=13-10
2,5у=10 |:2,5
У=4
2)
2х+3у=7
7х-3у=11 +
________
9х=18 |:9
х=2
Y= x^2 - 14
y = 6 - x
x^2 - 14 = 6 - x
x^2 + x - 20 = 0
D = 1 + 4*20 = 81 = 9^2
x1 = ( - 1 + 9)/2 = 4;
x2 = ( - 1 - 9)/2 = - 5;
x1 = 4;
y1 = 6 - 4 = 2;
x2 = - 5
y2 = 6 + 5 = 11
Ответ:
( 4 ; 2) ; ( - 5; 11)
<em><span>cosx=sin2x*cosx</span></em>