Answer:
Q2. (±5)
Q3. (±3)
Step-by-step explanation:
[tex]\bold{Q2.}\\\\4r^2-9=91\qquad\text{add 9 to both sides}\\\\4r^2-9+9=91+9\\\\4r^2=100\qquad\text{divide both sides by 4}\\\\\dfrac{4r^2}{4}=\dfrac{100}{4}\\\\r^2=25\to r=\pm\sqrt{25}\\\\\boxed{r=\pm5}[/tex]
[tex]\bold{Q3.}\\\\4r^2-7=29\qquad\text{add 7 to both sides}\\\\4r^2-7+7=29+7\\\\4r^2=36\qquad\text{divide both sides by 4}\\\\\dfrac{4r^2}{4}=\dfrac{36}{4}\\\\r^2=9\to r=\pm\sqrt9\\\\\boxed{r=\pm3}[/tex]
