This is Tony's family. His mother's name is Ann and his father's name is Nick.
Kelly and Sam are his grandmother and grandfather. And Pat is his sister. She is very cute.
1) по формуле...
2) вода испаряется, ее масса в кг уменьшится (и в процентах тоже),
а ягоды не испаряются, масса в кг останется неизменной...
3) при а=-4
А) 3(2x+y)-4(2y-x)=6x+3y-8y-4x=2x-5y
если х=0.2 у=-2/5, то 2*0.2-5*-2/5=4-(-2)=6