Question

1) 4-4x²=0
2)16x²+22x=38
3)x²=30+x
4)16-8x+x²=0
5)5x²-26x+5=0
6)10x²+5+3x=0
7)7b+b²=0​

Answer 1

1) 4-4x²=0 |÷4

1-x²=0

x²=1

x=±1

2)16x²+22x=38 |÷2

8x²+11x-19=0

√D =√11²-4*8*(-19)=√121+608=√729 = 27

x_1 = (-11+27)/16 =1

x_2 = (-11-27)/16 = -19/8

3)x²=30+x

√D =√(-1)²-4*1*30=√1-120=√-119 < 0

∅

4)16-8x+x²=0

x²-8x+16=0

(x-4)²=0

x-4=0

x=4

5)5x²-26x+5=0

√D =√(-26)²-4*5*5=√676-100=√576 = 24

x_1 = (26+24)/10 =5

x_2 = (26+24)/10  = 1/5

6)10x²+5+3x=0

√D =√3²-4*10*5=√9-200=√-191 < 0

∅

7)7b+b²=0​

b*(7+b) =0

b_1 = 0

7+b=0

b_2=-7