1)3(x-7)+5x 2)5(4-3x)+8x
3x-5x=21 20-15x+8x
2x=21 -7x=-20
x=21÷2 x=-20÷(-7)
x=10,5 x=-20/7
3)(y-4)×2+10y 4)(2y+5)×4-11y
2y-10y=8 8y-11y=-20
8y=8y -3y=-20
y=1 y=-20÷(-3)
y=-20/3
_____ _____ ______
(√3 6/7 - √5 1/4):√ 3/28 =-1
1) √ 3 6/7 - √ 5 1/4 = √27/7 -√21/4 = √27/√7 - √21/√4=
= ( √4·√27-√21·√7)/ √7·√4=(2·√9·3-√7·√3·√7)/√7·√4=(6√3-7√3)/√7·√4=
=-√3/√28
2) -√3/√28:√3/√28=-√3/√28·√28/√3=-1
1)13
2)15.68
3)20 дробь 9
4)2 дробь 9