Question

решите на уровне 7 класса
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Answer 1

Ответ:

1.1)(2x+9)(2x-9)=(2x)^2-9^2=4x^2-81

2)(8+5y)^2=64+80y+25y^2

3)(x-5)(x^2+5x+25)=(x-5)^3

4)(0,3c^5+1)(0,3c^5-1) = (0,3c^5)^2-1^2=0,09c^10-1

((4/5)a-10b^4)^2=(16/25)a^2-16ab^4+100b^8

5)(1+0,4p)(1-0,4p+0,16p^2)=(1+0,4p)^3

6)(7x-6)^2-(4x-3)(4x+3)=49x^2-84x+36-16x^2+9=33x^2-84x+45

2.1)12x^4y^3-16xy^2+4xy=4xy(3x^3y^2-4y+1)

2)10a^2-3y+15ay-2a=2a(5a-1)+3y(5a-1)=(2a+3y)(5a-1)

3)0,81-25c^2=(0,9-5c)(0,9+5c)

4)49x^2+28x+4=(7x+2)^2

5)64x^3+125=(4x+5)(16x^2-20x+25)

6)(3c+4)^2-49y^2=(3c+4-7y)(3c+4+7y)

3.1) 81,7^2-18,3^2=(81,7-18,3)(81,7+18,3)=63,4*100=6340

2)54^2-2*54*47+47^2=(54-47)^2=7^2=49

3)(63+2*63*27+27^2)/(59^2-31^2)=(63+27)^2/(59-31)(59+31)=100^2/28*90=3,97=4