Question

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

A. z = ±13/5
B. z = ±7/5
C. z = ±29/7
D. no real solutions

Answer 1

The answer is A. Z=+-13/5

Answer 2

Option A,
`z =` ±
`13/5`

Explanation:

Step 1: Add 140 both sides

`25z^2 - 140 = 29`

`25z^2 - 140 + 140 = 29 + 140`

`25z^2 = 169`

Step 2: Divide both sides by 25

`(25z^2)/(25) = (169)/(25)`

`z^2 = 6.76`

Step 3: Square root both sides

`√(z^2) = √(6.76)`

`z =` ±
`2.6`

`z =` ±
`13/5`

Answer: Option A,
`z =` ±
`13/5`