Question

Решить уравнение: А)15-(6-x)²=x(2-x)=? Б)(5x+2)²-25(x-3)(x+3)=29=?
В)64y²-49=0 .

Answer 1

15 - ( 6 - x )^2 = x( 2 - x )
15 - 36 + 12x - x^2  = 2x - x^2 
12x - 2x = 21
x = 2,1
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( 5x + 2 )^2 - 25( x - 3 )( x + 3 ) = 29
25x^2 + 20x + 4 - 25( x^2 - 9 ) = 29
25x^2 + 20x + 4 - 25x^2 + 225 = 29
20x = 29 - 229
x = - 200 : 20
x = - 10
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64y^2 - 49 = 0
( 8y - 7 )( 8y + 7 ) = 0
8y - 7 = 0
y1 = 7/8
8y + 7 = 0
y = - 7/8

Answer 2

1)15-(6-x)² = x(2 - x)15-36 + 12x - x²  = 2x - x²12x - 2x = 2110x = 21
x = 2,1

( 5x + 2 )² -25(x-3 )(x +3 ) = 2925x² + 20x + 4 - 25( x² - 9 ) = 2925x²+ 20x + 4 - 25x² + 225 = 2920x = 29 - 229x = - 200/20x =-10

64y² - 49 = 0( 8y - 7 )( 8y + 7 ) = 0   a²-b²=(a+b)(a-b)8y - 7 = 0   y (1)= 7/88y + 7 = 0   y (2)= - 7/8