-3-7<4x+x
-10<5x
x>-10/5
x>-2
0,25(√21-5)(√7+3√3)=0,25((√7√3-5)(√7+√3))=0,25(7√3+9√7-5√7-15√3)=
0,25(4√7-8√3)=√7-2√3
2√3+√7-2√3=√7
√7+(2√7-4)/(1+√7)=(√7+7+2√7-4)/(1+√7)=(3√7+3)/(1+√7)=3(√7+1)/(1+√7)=3
a^2+b^2=c^2a+b=49 => a=49-b(49-b)^2+b^2=(41)^2(49)^2-98b+b^2+b^2=16812b^2-98b+2401-1681=0 2b^2-98b+720=0 |:2b^2-49b+360=0(b-40)(b-9)=0b1=40, a1=49-40=9b2=9, a2=49-9=40S=ab/2S=40*9/2=180 (кв.м)
<span>Ответ: 180 кв. метров.</span>
Держи решение во вложении.