Add or subtract. Assume all variables represent positive real numbers.
-$\sqrt { 5 x ^ { 2 } } + 7 \sqrt { 80 x ^ { 2 } } - 3 \sqrt { 80 x ^ { 2 } }$
A) $17 x \sqrt { 102 }$
B) $4 \times \sqrt { 5 }$
C) $4 x \sqrt { 102 }$
D) $17 x \sqrt { 5 }$

Question

Quizplus · Accepted Answer

The expression simplifies to $x\sqrt{5} + 7x\sqrt{80} - 3x\sqrt{80}$, which further simplifies to $x\sqrt{5} + 4x\sqrt{80}$. Since $\sqrt{80} = \sqrt{16 \times 5} = 4\sqrt{5}$, the expression becomes $x\sqrt{5} + 4x \times 4\sqrt{5} = x\sqrt{5} + 16x\sqrt{5} = 17x\sqrt{5}$.

Add or Subtract 5x2+780x2−380x2\sqrt { 5 x ^ { 2 } } + 7 \sqrt { 80 x ^ { 2 } } - 3 \sqrt { 80 x ^ { 2 } }5x2​+780x2​−380x2​

Add or Subtract $\sqrt { 5 x ^ { 2 } } + 7 \sqrt { 80 x ^ { 2 } } - 3 \sqrt { 80 x ^ { 2 } }$