Question

If k√28+√63-√7=0 find k

Answer 1

= > k√28 + √63 - √7 = 0


= > k√{ 28 } + √{ 63 } - √{ 7 } = 0


= > k√{ 7 × 4 } + √{ 7 × 9 } - √7 = 0


= > k√{ 7 × 2² } + 4√{ 7 × 3² } - √7 = 0


= > 2k√7 + 12√7 - √7 = 0


= > √7 { 2k + 12 - 1 } = 0


= > 2k + 11 = 0


= > 2k = - 11


$\boxed{ \bold{ = > x = - \frac{11}{2} }}$

Answer 2

ksqrt28 ~ sqrt7 - sqrt63. squaring both sides. 28K^2 ~ 7 + 63 - 2 sqrt 441. 28k^2 ~ 70 - 2*21. 28 k^2 ~ 70-42. 28k^2 ~ 28. so k~1