Каждой параболе поставь в соответствие ее вершину:
А) у = х² + 6х 3) (–3; –9)
Б) у = х² + 6х + 9 2) (–3; 0)
В) у = 6х – х² 1) (3; 9)
Упрости выражение:
а) (а – 3)(а + 3) – (2 – а)²=a²-9-4+4a-a²=4a-13;
б) (2a + 3b)(3b – 2a) – (a – b)(b + a)=9b²-4a²-a²+b²=10b²-5a²;
в) (x – 2)(x + 2)(x – 3)(x + 3)=(x²-4)(x²-9)=x⁴-13x²+36;
г) (5 – a)² – (а + 1)² + 5(2 – a)(2 + a)=25-10a-a²-a²-2a-1+20-5a²=-7a²-12a+44.
Найди площадь равнобедренного треугольника, основание которого равно 8, а боковая сторона 5.
высота треугольника проведенная к основанию=3 (5*5-8/2 *8/2=9)
S=0.5*8*3=12
ответ 3
Каждому квадратному трехчлену поставь в соответствие его разложение на множители:
А) х² – 3х + 2 1) (х – 1 )(х – 2)
Б) х² – 2х – 3 2) (х + 1)(х – 3)
В) 2х² + х – 3 3) (х – 1)(2х + 3)
Задачи:
а) Найти периметр ромба, если длина его меньшей диагонали равна 7 см, а один из его углов равен 60⁰.
меньшая диагональ=стороне ромба, т. к получается равносторонний треугольник, значит Р= 4*7=28
б) Диагональ параллелограмма делит его на два равносторонних треугольника. Докажи, что этот параллелограмм —ромб, и найди угол, который образует его большая диагональ со сторонами.
Равносторонние треугольники, значит углы по 60⁰.Каждая сторона равна диагонали, значит все стороны равны⇒ ромб.Угол=60⁰
Реши неравенство, изобрази на числовой прямой множество его решений и запиши ответ с обозначений:
1) 12 + х > 18; х>6
2)
3) 6 + х < 3 – 2х; 3x<-3, x<-1
4) 4 + 12х > 7 + 13х; -x>3, x<-3
5) 3(2 + х) > 4 – х; 6+3x>4-x, 4x>-2, x>0.5
6)
Реши уравнение:
1) | 2x – 3 | = 5; 2x-3=5,2x=8, x=4 и 2x-3=-5, 2x=-2, x=-1 ответ -1; 4
2) | 2 + 7x | = 1; х=-1/7 и х=-3/7
3) | 5 – 3x | = 0; х=5/3
4) | 2x + 4 | = –2.решений нет
Из формулы у = kx + b выразите угловой коэффициент k.
k=(y-b)/x
Каждому квадратному уравнению поставьте в соответствие его корни
А) х² – 2х – 8 = 0, 2) – 2; 4,
Б) 5х² – 3х – 2 = 0, 1) – 0,4; 1,
В) х²+ 6х + 9 = 0 3) –3.
Вычислите периметр прямоугольника АВСD, если биссектриса угла В пересекает сторону АD в точке Е и делит ее на отрезки АЕ = 17 и ЕD = 21.
AE=AB=17
AD=AE+ED=38
P=2*(17+38)=110
b) My friend wasn't waiting for me when I arrived late. 7.a) When did he have the accident? -As he was climbing up the ladder. b) When was he having the accident? -As he was climbing up the ladder. 8.a) l read a book when she sent me an SMS. b) l was reading a book when she sent me am SMS. 9.a) Did you eеat lunch when the fire alarm rang? b) Were you eating luncn when the fire alarm rang. 10.a) lt was a beautiful day The sun shone and there wasn't a cloud in the sky. b) lt was a beautiful day. The sun was shining and there wasn't a cloud in the sky.
Look at the of sentences below. Both of them are grammatically correct. Choose one sentence in each pair, a or b, that is more logical. 1.a) lt rained heavily when I ran for the bus. B) lt was raining heavily when I ran for the bus. 2.a) The rain jjust came into the station when we arrived on the platform. b) The train was just coming into the station when we arrived on the platform. 3.a) He broke his leg while riding his bike at the weekend. b) He was breaking his leg while riding his bike at the weekend. 4.a) While I was watching TV, someone knocked on the window. bjWhile I was watching TV, someone was knocked on the window. 5 a) No wonder she fell off her bike. She didnt Innk here che iwac in
6 Complete the sentences with when or while. 1) The boys were playing football ... the ball flew into the window. 2) Ronny was painting the fence ... the bucket of paint turned over. 3) Denny was putting a tent ... the girls were gathering wood for fire. 4) Rita was sleeping .. the alarm- rang. 5) Nelly was peeling potatоes her sister was cutting chicken into pieces. 6) Nigel was skiing he fell down and broke his leg. 7) They were arguing ... Mrs Elliot entered the room. 8) ... my mother was watching her favorite show on TV, father making coffee. 9) She was tying a letter some mistakes. 10) They were driving towards the village it started clock she found to snow.
я не понимаю
Объяснение:
я учусь в 4 класе