(x + 4)(x - 7) + (x+ 3)(10 - x) при x = 0.75

Question

(x + 4)(x - 7) + (x+ 3)(10 - x) при x = 0.75

Answer 1

(х + 4)(х - 7) + (х + 3)(10 - х) = х² - 7х + 4х - 28 + 10х - х² + 30 - 3х = 4х + 2

при х = 0,75

4 • 0,75 + 2 = 5

Answer 2

Решение:

(x+4)(x-7)+(x+3)(10-x)=

x²-7x+4x-28+10x-x²+30-3x=

4x+2= 2(2x+1)

при x=0.75 :

2(2×0.75+1)=2 × 2.5 =5