Verify the Equality: (y+9)(2y-2) = 2y²-20y+18

Question

Is equality correct?

(y+9)(2y2)=2y220y+18 (y+9)(2y-2)=2y^2-20y+18

Video Solution

Step-by-Step Solution

To determine the correctness of the equation (y+9)(2y2)=2y220y+18 (y+9)(2y-2)=2y^2-20y+18 , follow these steps:

  • Step 1: Expand the left-hand side expression using the distributive property.

Start by applying the distributive property:
(y+9)(2y2)=y2y+y(2)+92y+9(2)(y + 9)(2y - 2) = y \cdot 2y + y \cdot (-2) + 9 \cdot 2y + 9 \cdot (-2)

  • Step 2: Calculate each term.

y2y=2y2y \cdot 2y = 2y^2
y(2)=2yy \cdot (-2) = -2y
92y=18y9 \cdot 2y = 18y
9(2)=189 \cdot (-2) = -18

  • Step 3: Combine the terms.

Now, combine the terms:
2y22y+18y182y^2 - 2y + 18y - 18

  • Step 4: Simplify the expression.

This simplifies to:
2y2+16y182y^2 + 16y - 18

  • Step 5: Compare with the right-hand side.

The expression 2y2+16y182y^2 + 16y - 18 does not match the right-hand side 2y220y+182y^2 - 20y + 18.

Therefore, the original expression is not correct as given. The discrepancy appears to be in the linear terms. If we adjust one factor in the left-hand side, for example changing y+9y + 9 to y9y - 9, we would get:

(y9)(2y2)=2y220y+18(y - 9)(2y - 2) = 2y^2 - 20y + 18, which would match the right side correctly.

Hence, the correct statement is: No, it must be (y9) (y-9) instead of (y+9) (y+9) .

Answer

No, it must be (y9) (y-9) instead of (y+9) (y+9)