Chapter 1: Q 1.42. (page 34)

Evaluate: $4 x^{2} - x y + 5 y^{2}$ when $x = - 2, y = 3$ .

Short Answer

Expert verified

The value is 67.

Step by step solution

Step 1. Given Information.

The given expression is $4 x^{2} - x y + 5 y^{2}$ and the values of the variables are $x = - 2$ and $y = 3$ .

Step 2. Substitute the values.

Substitute $- 2$ for $x$ and 3 for $y$ into the given expression $4 x^{2} - x y + 5 y^{2}$ .

$4 {(- 2)}^{2} - (- 2) (3) + 5 {(3)}^{2}$

Step 3. Calculate the exponents.

The value of the exponents are ${(- 2)}^{2} = 4$ and ${(3)}^{2} = 9$ . Simplify the exponents in the obtained expression.

$4 \cdot (4) - (- 2) (3) + 5 \cdot (9)$

Step 4. Multiply.

Perform multiplication from left to right.

$16 - (- 6) + 45$

Step 5. Simplify.

Add and subtract from left to right.

$\begin{array}{rcl} 16 + 6 + 45 & = & 22 + 45 \\ = & 67 \end{array}$

Step 6. Conclusion.

The required value is 67.

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Evaluate: $4 x^{2} - x y + 5 y^{2}$ when $x = - 2, y = 3$ .

Short Answer

Step by step solution

Step 1. Given Information.

Step 2. Substitute the values.

Step 3. Calculate the exponents.

Step 4. Multiply.

Step 5. Simplify.

Step 6. Conclusion.

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Evaluate:4x2-xy+5y2whenx=-2,y=3.

Short Answer

Step by step solution

Step 1. Given Information.

Step 2. Substitute the values.

Step 3. Calculate the exponents.

Step 4. Multiply.

Step 5. Simplify.

Step 6. Conclusion.

One App. One Place for Learning.

Most popular questions from this chapter

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Evaluate: $4 x^{2} - x y + 5 y^{2}$ when $x = - 2, y = 3$ .