Solve (5 + sqrt(7))(5 - sqrt(7)) | Equatix - Math Solver

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Example

3(r+2s)=2t-4

a⋅(b-2)=3b

3(r+2s)=2t-4

a⋅(b-2)=3b

Question

$$(5+\sqrt{7})(5-\sqrt{7})$$

Evaluate

$18$

Solution Steps

Multiplication can be transformed into difference of squares using the rule: $\left(a-b\right)\left(a+b\right)=a^{2}-b^{2}$.

$$5^{2}-\left(\sqrt{7}\right)^{2}$$

Calculate $5$ to the power of $2$ and get $25$.

$$25-\left(\sqrt{7}\right)^{2}$$

The square of $\sqrt{7}$ is $7$.

$$25-7$$

Subtract $7$ from $25$ to get $18$.

$$18$$

Factor

$2\times 3^{2}$