Solve 63b^2/14b+35

$$\frac { 63 b ^ { 2 } } { 14 b + 35 }$$

Evaluate

$$\frac{9b^{2}}{2b+5}$$

Short Solution Steps

Factor the expressions that are not already factored.

$$\frac{63b^{2}}{7\left(2b+5\right)}$$

Cancel out 7 in both numerator and denominator.

$$\frac{9b^{2}}{2b+5}$$

Differentiate w.r.t. b

$$\frac{18b\left(b+5\right)}{\left(2b+5\right)^{2}}$$

Steps Using Derivative Rule for Quotient

For any two differentiable functions, the derivative of the quotient of two functions is the denominator times the derivative of the numerator minus the numerator times the derivative of the denominator, all divided by the denominator squared.

$$\frac{\left(14b^{1}+35\right)\frac{\mathrm{d}}{\mathrm{d}b}(63b^{2})-63b^{2}\frac{\mathrm{d}}{\mathrm{d}b}(14b^{1}+35)}{\left(14b^{1}+35\right)^{2}}$$

The derivative of a polynomial is the sum of the derivatives of its terms. The derivative of a constant term is 0. The derivative of ax^{n} is nax^{n-1}.

$$\frac{\left(14b^{1}+35\right)\times 2\times 63b^{2-1}-63b^{2}\times 14b^{1-1}}{\left(14b^{1}+35\right)^{2}}$$

Do the arithmetic.

$$\frac{\left(14b^{1}+35\right)\times 126b^{1}-63b^{2}\times 14b^{0}}{\left(14b^{1}+35\right)^{2}}$$

Expand using distributive property.

$$\frac{14b^{1}\times 126b^{1}+35\times 126b^{1}-63b^{2}\times 14b^{0}}{\left(14b^{1}+35\right)^{2}}$$

To multiply powers of the same base, add their exponents.

$$\frac{14\times 126b^{1+1}+35\times 126b^{1}-63\times 14b^{2}}{\left(14b^{1}+35\right)^{2}}$$

Do the arithmetic.

$$\frac{1764b^{2}+4410b^{1}-882b^{2}}{\left(14b^{1}+35\right)^{2}}$$

Combine like terms.

$$\frac{\left(1764-882\right)b^{2}+4410b^{1}}{\left(14b^{1}+35\right)^{2}}$$

Subtract 882 from 1764.

$$\frac{882b^{2}+4410b^{1}}{\left(14b^{1}+35\right)^{2}}$$

Factor out 882b.

$$\frac{882b\left(b^{1}+5b^{0}\right)}{\left(14b^{1}+35\right)^{2}}$$

For any term t, t^{1}=t.

$$\frac{882b\left(b+5b^{0}\right)}{\left(14b+35\right)^{2}}$$

For any term t except 0, t^{0}=1.

$$\frac{882b\left(b+5\times 1\right)}{\left(14b+35\right)^{2}}$$

For any term t, t\times 1=t and 1t=t.

$$\frac{882b\left(b+5\right)}{\left(14b+35\right)^{2}}$$