The area of a bookshelf is 216 square inches. If the length of the bookshelf is 36 inches. What is the width of the bookshelf?
2 answers:
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Answer:
7. x = -2 +/-
8. x = 2 or x = 6
9. x = -2 +/-
10. t = -3 +/-
Step-by-step explanation:
7. Subtract 320 from both sides: 4(x + 2)^2 = -320
Divide by 4: (x + 2)^2 = -80
Square root both sides: x + 2 = +/- . We need to add the imaginary i to this: +/-
= +/-
= +/-
Subtract 2 from both sides: x = -2 +/-
8. Add 18 to both sides: 7(x - 4)^2 = 28
Divide by 7: (x - 4)^2 = 4
Square root both sides: x - 4 = +/- 2
Add 4 to both sides: x = 4 +/- 2 ⇒ x = 2 or x = 6
9. Add 5 to both sides: -2(x + 2)^2 = 13
Divide by -2: (x + 2)^2 = -13/2
Square root both sides: x + 2 = +/- . We again need i: +/-
= +/-
+/-
Subtract 2 from both sides: x = -2 +/-
10. Multiply by 5 on both sides: (t + 3)^2 = 35
Square root both sides: t + 3 = +/-
Subtract 3: t = -3 +/-
Hope this helps!