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

$\frac{5r^2}{5} =\frac{80}{5}$

$r^2=16$

now, we can take sqrt both sides

and we get

$r=4 , r=-4$

so,

{±4}..........Answer