<span>(36х+6х):24=17
42x=17*24
42x=408
x=408:42
x=9 5/7
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</span><span>445а-278а при а=300
</span>445а-278а=167a
167*300=50100
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<span>67х+25+15х+68 при х=39
</span><span>67х+25+15х+68 =82x+93=82*39+93=3198+93=3291</span>
4cos⁴x-3cos2x-1=0
cos2x=2cos²x-1
4(cos²x)²-3*(2cos²x-1)-1=0
cos²x=t, t∈[ 0 ; 1 ]
4t²-6t+2=0
2t²-3t+1=0
D=1
t₁=1/2, t₂=1
t₁=1/2
cos²x=1/2, cosx=+-√(1/2), cosx=+-√2/2
1. cosx=√2/2, <u>x₁=+-π/4+2πn, n∈Z</u>
2. cosx=-√2/2, x=+-(π-arccos√2/2)+2πn, n∈Z, <u>x₂=+-3π/4+2πn, n∈z</u>
t₂=1
cos²x=1, cosx=+-1
cosx=-1, <u>x₃=π+2πn, n∈Z</u>
cosx=1, <u>x₄=2πn, n∈Z</u>
(5+6)=11
(8+4)=12
11+12+10=33
33*0=0
или проще говоря : (5+6+8+4+10)*0=0
+86+49=135-вот такой ответ