Question

which equations are correct? all that apply-2b^3(6b^2+5)= - 12b^5-10b^3- 7x^2(4x^3+2)= - 28x^6-14x^2- 3y^4(5y^2+2)= - 15y^8- 6y^4- 5d^3(3d^2+4)= - 15d^5-20d^3

Answer 1

Verify each case

Part 1

we have

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

solve the left side

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

so

equation 1 is correct

Part 2

- 7x^2(4x^3+2)= - 28x^6-14x^2

solve the left side

- 7x^2(4x^3+2)=-28x^5-14x^2

so

equation 2 is not correct

Part 3

- 3y^4(5y^2+2)= - 15y^8- 6y^4

solve the left side

- 3y^4(5y^2+2)=-15y^6-6y^4

so

equation 3 is not correct

Part 4

- 5d^3(3d^2+4)= - 15d^5-20d^3​

solve the left side

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

so

equation 4 is correct