Question

Solve 5r2 – 12 = 68. {±4} {±5} {±3} {±6}

Answer 1

we are given

`5r^2-12=68`

Since, we have to solve for r

so, firstly we will isolate r terms

so, we will move 12 on right side

we can add both sides by 12

`5r^2-12+12=68+12`

`5r^2=80`

now, we can divide both sides by 5

`(5r^2)/(5) =(80)/(5)`

`r^2=16`

now, we can take sqrt both sides

and we get

`r=4 , r=-4`

so,

{±4}..........Answer