Elevii clasei a iv-a se informeaza despre preturile unor obiecte: 3 aparate foto de acelasi fel si un laptop costa 2700lei, iar 5 aparate foto si 2 laptopuri, de acelasi fel ca primele costa,4900lei. cat costa un aparat foto? dar un laptop? prin metoda compaatiei va rog ! urgent

Laptops are 1200 each and cameras are 500 each.

Using elimination:
3c+l=2700
5c+2l=4900

We will make the coefficients of l the same by multiplying the top equation by 2:
2(3c+l=2700)
6c+2l=5400

Our system is now
6c+2l=5400
5c+2l=4900

Subtract the bottom equation:
6c+2l=5400
-(5c+2l=4900)

We have
1c=500
So each camera is 500.

Substitute that in our original first equation:
3(500)+l=2700
1500+l=2700
1500+l-1500=2700-1500
l=1200

Intersecting secant-tangent theorem states that if a tangent segment and a secant segment are drawn to a circle from an exterior point, then the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.so to break it down: 1. pq acts as the tangent and ps as the secant with an intersection at p.sr = 21rp = 3x + 3pq = 4x + 4following to equation: tangent squared = the two segments multiplied by each otherso (4x + 4) ^ 2 = (3x + 3) • (21) simplifies to 16x^2 - 31x - 47 = 0 or (16x - 47)(x + 1) x = -1 or x = 47/162. pq acts as the tangent and ps as the secant with an intersection at p (again! )sr = 16rp = xpq = 15(15) ^ 2 = 16 • x225 = 16xx = 225/163. the interesting chords are proportional to each other so a ratio is possible to set up: ap dp 10 3 + x = = —— = pc pb 8 xcross multiple to get 10x = (3 + x)(8)x = 12