Question

Which equations are correct?

Select each correct answer.



−7x2(4x3+2)=−28x6−14x2
−5d3(3d2+4)=−15d5−20d3
−2b3(6b2+5)=−12b5−10b3
−3y4(5y2+2)=−15y8−6y4

Answer 1

A and D if its not right tell me i'm only a beginner i would like to learn from my mistakes

Answer 2

Answer:

$-5d^3(3d^2+4)=-15d^5-20d^3$

$-2b^3(6b^2+5)=-12b^5-10b^3$

Step-by-step explanation:

Given equations are correct if the left side and right side of the equation are same,

First option : $-7x^2(4x^3+2)=(-7x^2)(4x^3)+(-7x^2)(2)$

$=-28x^{2+3}-14x^2$

$=-28x^5-14x^2\neq -28x^6-14x^2$

Second option : $-5d^3(3d^2+4)=(-5d^3)(3d^2)+(-5d^3)(4)$

$=-15d^{3+2}-20d^3$

$=-15d^5-20d^3$

Third option : $-2b^3(6b^2+5)=(-2b^3)(6b^2)+(-2b^3)(5)$

$=-12b^{3+2}-10b^3$

$=-12b^5-10b^3$

Fourth option : $-3y^4(5y^2+2)=(-3y^4)(5y^2)+(-3y^4)(2)$

$=-15y^{4+2}-6y^4$

$=-15y^6-6y^4\neq -15y^8-6y^4$