(4+√7) / (√7+1)²=(4+√7)/(7+2√7+1)=(4+√7)/(8+2√7)=<span>(4+√7)/2(4+√7)=1/2</span>
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<em>f(x) = 2x - 5</em>
а) f(0) = 2·0 - 5 = -5
f(-1,5) = 2·(-1,5) - 5 = -3 - 5 = -8
б) f(x) = 18
2x - 5 = 18; 2x = 23; x = 11,5
f(x) = 0
2x - 5 = 0; 2x = 5; x = 2,5