Answer:
-6x^2 y^3 = B
Step-by-step explanation:
42x^5y^4=(-7x^3y)(B)
Solve for B
Divide by -7
42x^5y^4/-7=(-7x^3y)(B)/-7
-6 x^5 y^4 = x^3 y B
Divide by x^3
-6 x^5 y^4/x^3 = x^3 y B/x^3
-6 x^5/x^3 y^4 = By
-6 x^2 y^4
Divide by y
-6x^2 y^4/y = By/y
-6x^2 y^3 = B
