Agar garis y=×+c menyinggung lingkaran ×^2+y^2=25 maka nilai c adalah

[tex]ax + by + c = 0 = > x - y + c = 0 \\ (x1.y1) = > (0.0) \: \: r = 5 \\ r = | \frac{ax1 + by1 + c}{ \sqrt{ {a}^{2} + {b}^{2} } } | \\ 5 = | \frac{(1)(0) + ( - 1)(0) + c}{ \sqrt{ {1}^{2} + {( - 1)}^{2} } } | \\ 5 = | \frac{c}{ \sqrt{2} } | \\ 5 = \frac{c}{ \sqrt{2} } \\ c = 5 \sqrt{2} [/tex]