15.A lamp is on sale at £22.05 This is a 10% reduction of the normal price. What was the price of the lamp before the reduction?

24.5

Step-by-step explanation:

Sale price = 90% of normal price = 22.05

Normal price=24.5

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

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step-by-step explanation: