Question

Solve the equation 25z2 + 140 = −29 by using square roots.

Answer 1

Answer:

z is 13i/5

Step-by-step explanation:

${ \sf{25 {z}^{2} + 140 = - 29}} \\ { \sf{25 {z}^{2} = - 169 }} \\ { \sf{ \sqrt{25 {z}^{2} } = \sqrt{ - 169} }} \\ { \sf{5z = \sqrt{169 \times - 1} }} \\ { \sf{5z = \sqrt{169} \times \sqrt{ - 1} }} \\ { \sf{5z = 13 \times \sqrt{ {i}^{2} } }} \\ { \sf{5z = 13i}} \\ { \sf{z = \frac{13i}{5} }}$

Answer 2

Answer:

13i/5

Step-by-step explanation:

25z^2+140=-29      subtract 140 from both sides

25z^2=-169          now square root both sides.

$\sqrt{25z^{2} }$=$\sqrt{-169}$     a negative root forms i

5z=13i                    

z=13i/5